Variable flow infusion pump system

ABSTRACT

An implantable infusion pump system is disclosed. The pump system preferably includes an implantable pump and a programmable module. The module may provide for varying flow rates of fluid being dispensed from the pump or may provide for a constant flow rate of such fluid. In the case of varying flow rate capabilities, the module preferably includes one or more sensors to determine information relating to the flow rate, electronics for analyzing the flow rate information, and a mechanism for physically altering the flow rate. In certain embodiments, the module includes a hermetically sealed housing. Methods of dispensing a medicament to a patient utilizing such a system are also disclosed, as are variations of the pump system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 12/621,799, filed on Nov. 19, 2009, which is a continuation ofU.S. application Ser. No. 11/601,586, filed on Nov. 17, 2006 (now U.S.Pat. No. 7,637,892), which is a continuation-in-part of U.S. applicationSer. No. 11/125,586, filed on May 10, 2005, U.S. application Ser. No.11/126,101, filed on May 10, 2005 and U.S. application Ser. No.11/157,437, filed on Jun. 21, 2005, the disclosures of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to implantable devices, and moreparticularly to reduced size implantable pumps and programmableimplantable pumps allowing for variable flow rates in deliveringmedication or other fluid to a selected site in the human body.

Implantable pumps have been well known and widely utilized for manyyears. Typically, pumps of this type are implanted into patients whorequire the delivery of active substances or medication fluids tospecific areas of their body. For example, patients that areexperiencing severe pain may require painkillers daily or multiple timesper day. Absent the use of an implantable pump or the like, a patient ofthis type would be subjected to one or more painful injections of suchmedication fluids. In the case of pain associated with more remote areasof the body, such as the spine, these injections may be extremelydifficult to administer and particularly painful for the patient.Furthermore, attempting to treat conditions such as this through oral orintravascular administration of medication often requires higher dosesof medication and may cause severe side effects. Therefore, it is widelyrecognized that utilizing an implantable pump may be beneficial to botha patient and the treating physician.

Many implantable pump designs have been proposed. For example, commonlyinvented U.S. Pat. No. 4,969,873 (“the '873 patent”), the disclosure ofwhich is hereby incorporated by reference herein, teaches one suchdesign. The '873 is an example of a constant flow pump, which typicallyinclude a housing having two chambers, a first chamber for holding thespecific medication fluid to be administered and a second chamber forholding a propellant. A flexible membrane may separate the two chamberssuch that expansion of the propellant in the second chamber pushes themedication fluid out of the first chamber. This type of pump alsotypically includes an outlet opening connected to a catheter fordirecting the medication fluid to the desired area of the body, areplenishment opening for allowing for refilling of medication fluidinto the first chamber and a bolus opening for allowing the directintroduction of a substance through the catheter without introductioninto the first chamber. Both the replenishment opening and the bolusopening are typically covered by a septum that allows a needle orsimilar device to be passed through it, but properly seals the openingsupon removal of the needle. As pumps of this type provide a constantflow of medication fluid to the specific area of the body, they must berefilled periodically with a proper concentration of medication fluidsuited for extended release.

Although clearly beneficial to patients and doctors that utilize them,one area in which such constant flow implantable pumps can be improved,is in their overall size. Typically, such pumps require rather bulkyouter housings, or casings, for accommodating the aforementionedmedication and propellant chambers, and septa associated therewith.Often times, implantable pumps are limited to rather small areas withinthe body. Depending upon the size of the patient for which the pump isimplanted, this limited area may be even further limited. For example, aperson having smaller body features, or those containing abnormalanatomy, may present a doctor implanting a constant flow pump with someadded difficulty. Further, patients may be uncomfortable having standardsized constant flow pumps implanted in them. Such pumps are often timescapable of being felt from the exterior of the patient.

Implantable pumps may also be of the programmable type. Pumps of thistype provide variable flow rates, typically through the use of asolenoid pump or a peristaltic pump. In the solenoid pump, the flow rateof medication fluid can be controlled by changing the stroke rate of thepump. In the peristaltic pump, the flow rate can be controlled bychanging the roller velocity of the pump. However, both of these typesof programmable pumps require intricate designs and complicatedcontrolling mechanisms. As such, it would be more desirable to utilizepumps having designs similar to the aforementioned constant flow pumps.

However, the benefit of providing a variable flow rate pump cannot beforgotten. While a constant flow of a medication such as a painkillermay indeed be useful in dulling chronic pain, it is very common forpatients to experience more intense pain. At times of this heightenedpain, it would be advantageous to be able to vary the flow rate of painkiller to provide for more relief. However, constant flow rate pumpstypically may only provide such relief by allowing for direct injectionsof painkillers or the like through the aforementioned bolus port, whichprovides direct access to the affirmed area. While indeed useful, thismethod amounts to nothing more than additional painful injections,something the pump is designed to circumvent.

Therefore, there exists a need for an implantable constant flow pump,which allows for a reduced overall size, as well as an implantable pumpthat combines the simplistic design of a constant flow rate type pumpand means for varying its flow rate, without requiring the use of thecomplex solutions provided by known programmable pumps.

SUMMARY OF THE INVENTION

A first aspect of the present invention is a reduced size implantabledevice for dispensing an active substance to a patient. The implantabledevice of a first embodiment of this first aspect includes a housingdefining an active substance chamber in fluid communication with anoutlet for delivering the active substance to a target site within thepatient and a propellant chamber adjacent the active substance chamber.The implantable device further includes an undulating flexible membraneseparating the active substance and propellant chambers, wherein theactive substance chamber has an undulating surface including a centralconvex portion flanked by at least two concave portions, the undulatingsurface cooperating with the undulating flexible membrane.

In accordance with this first embodiment of the first aspect of thepresent invention, the propellant chamber may contain a propellantcapable of expanding isobarically where the propellant cooperates withthe flexible membrane to reduce the volume of the active substancechamber upon expansion of the propellant. The cooperating undulatingsurface of the active substance chamber and the undulating flexiblemembrane preferably meet upon complete expansion of the propellant. Theimplantable device may further include a replenishment opening in thehousing in fluid communication with the active substance chamber, and afirst septum sealing the opening. The replenishment opening may belocated within the central convex portion of the undulating surface ofthe active substance chamber so as to lower the overall height of thehousing of the implantable device. Additionally, the housing may includetwo portions being constructed so as to screw together. The two portionsmay be constructed of PEEK. The two portions may be configured so as tocapture the membrane therebetween. Finally, the housing may also includea locking portion and/or a septum retaining member.

A second embodiment of this first aspect of the present invention is yetanother implantable device for dispensing an active substance to apatient. The implantable device according to this second embodimentincludes a housing defining a chamber and an outlet in fluidcommunication with the chamber for delivering the active substance to atarget site within the patient, the housing having a first portion and asecond portion, where the first and second portions are constructed ofPEEK and screwed together.

A third embodiment of this first aspect of the present invention is yetanother implantable device for dispensing an active substance to apatient. The implantable device according to this third embodimentincludes a housing including a top portion, a bottom portion and alocking portion. The housing defines a propellant chamber and an activesubstance chamber in fluid communication with an outlet. The implantabledevice preferably also includes a membrane retained between the top andbottom portions, the membrane separating the active substance andpropellant chambers. In a fully assembled stated, the top and bottomportions are preferably placed together and the locking portion engagesone of the top or bottom portions to retain the top and bottom portionstogether.

A fourth embodiment of this first aspect of the present inventionrelates to a method of assembling a reduced size implantable pump. Themethod of this embodiment includes the steps of placing together a topportion and a bottom portion to retain a membrane therebetween, andscrewing a locking portion into the top portion or the bottom portion toretain the top and bottom portions together.

A second aspect of the present invention includes an implantable devicefor dispensing an active substance to a patient including a housingdefining a chamber, said housing having an outlet for delivering theactive substance to a target site within the patient, the outlet influid communication with the chamber and means for varying the flow rateof the active substance between the chamber and the outlet. The chamber,in accordance with this second aspect of the present invention, mayinclude an active substance chamber in fluid communication with theoutlet and a propellant chamber, the active substance and propellantchambers being separated by a flexible membrane. The propellant chambermay contain a propellant capable of expanding isobarically andcooperating with the flexible membrane to reduce the volume of theactive substance chamber upon expansion of the propellant. The housingof the implantable device may include an opening in fluid communicationwith the active substance chamber and a first septum sealing theopening. The housing may further include an annular opening incommunication with the outlet and a second septum sealing the annularopening.

In a first embodiment of this second aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude an elongated polymer filament having a cross sectionaldimension. The filament, in accordance with this embodiment, ispreferably located in a capillary and is preferably capable of beingelongated to reduce the cross sectional dimension. In certain examples,the filament is located centrally within the capillary, in others, it islocated eccentrically. The filament may have a uniform cross section, asubstantially circular cross section, non-uniform cross section and thelike along its length. Further, this first embodiment may furtherinclude means for elongating the filament.

In a second embodiment of this second aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude a first hollow cylinder having a threaded exterior surface and asecond hollow cylinder having a threaded interior surface. The firsthollow cylinder is axially received within the second hollow cylinder,such that the threaded exterior surface of the first cylinder engagesthe threaded interior surface of the second cylinder. In thisembodiment, the axial movement of the first cylinder with respect to thesecond cylinder varies the flow rate of the active substance.

In a third embodiment of this second aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude a hollow tubular element having a cross section that is capableof being varied. This third embodiment may also include a capillary influid communication between the chamber and the outlet, where thetubular element is located therein. The hollow tubular element inaccordance with this embodiment may be centrally or eccentricallylocated within the capillary.

In a fourth embodiment of this second aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude an elongate insert having a longitudinally varying cross sectionalong its length. Movement of this elongate insert may increase ordecrease the flow rate of the active substance.

A third aspect of the present invention includes an implantable devicefor dispensing an active substance to a patient including a housingdefining a chamber, said housing having an outlet for delivering theactive substance to a target site within the patient, the outlet influid communication with the chamber. The implantable device alsoincludes a capillary in fluid communication between the chamber and theoutlet, the capillary having an inner surface and a flow control elementreceived within the capillary. The element has an outer surface opposingthe inner surface of the capillary defining therebetween a passagewayfor the flow of the active substance therethrough. The outer surface ofthe element is preferably movable relative to the inner surface of thecapillary to alter the flow of the active substance therethrough. Themovement of the outer surface of the element may alter the shape and/orsize of the passageway.

In a first embodiment of this third aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude an elongated polymer filament having a cross sectionaldimension. The filament, in accordance with this embodiment, ispreferably located in a capillary and is preferably capable of beingelongated to reduce the cross sectional dimension. In certain examples,the filament is located centrally within the capillary, in others, it islocated eccentrically. The filament may have a uniform cross section, asubstantially circular cross section, non-uniform cross section and thelike along its length. Further, this first embodiment may furtherinclude means for elongating the filament.

In a second embodiment of this third aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude a first hollow cylinder having a threaded exterior surface and asecond hollow cylinder having a threaded interior surface. The firsthollow cylinder is axially received within the second hollow cylinder,such that the threaded exterior surface of the first cylinder engagesthe threaded interior surface of the second cylinder. In thisembodiment, the axial movement of the first cylinder with respect to thesecond cylinder varies the flow rate of the active substance.

In a third embodiment of this third aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude a hollow tubular element having a cross section that is capableof being varied. This third embodiment may also include a capillary influid communication between the chamber and the outlet, where thetubular element is located therein. The hollow tubular element inaccordance with this embodiment may be centrally or eccentricallylocated within the capillary.

In a fourth embodiment of this third aspect, the means for varying theflow rate of the active substance between the chamber and the outlet mayinclude an elongate insert having a longitudinally varying cross sectionalong its length. Movement of this elongate insert may increase ordecrease the flow rate of the active substance.

A fourth aspect of the present invention includes a resistor for varyingthe flow rate of a fluid from a first point to a second point includinga capillary having an inner surface and a flow control element receivedwith the capillary. The element has an outer surface opposing the innersurface of the capillary such that a passageway is defined for the flowof fluid therethrough. The outer surface of the element is preferablymoveable relative to the inner surface of the capillary to alter theflow of the fluid therethrough. The movement of the outer surface of theelement may alter the shape and/or size of the passageway. It is notedthat this aspect may be utilized in conjunction with an implantabledevice such as an implantable pump for delivering a medicament to a sitewithin a patient. Embodiments in accordance with the third aspect may besimilar to those discussed above in relation to the first and secondaspects of the present invention.

A fifth aspect of the present invention includes a method of varying theflow rate of an active substance being dispensed to a patient. Thismethod includes the steps of providing an implantable device including acapillary having an inner surface and a flow control element receivedwithin the capillary. The element preferably has an outer surfaceopposing the inner surface of the capillary such that a passageway forthe flow of the active substance therethrough is defined therebetweenfor dispensing the active substance to a target site within a patient.Further the method includes the step of moving the element relative tothe inner surface of the capillary to alter the flow rate of the activesubstance therethrough. This moving step may alter the size and/or shapeof the passageway.

Yet another aspect of the present invention is an implantable infusionpump system for dispensing an active substance at one or varying flowrates to a patient. The system may include a constant flow pump having ahousing defining an active substance chamber, an outlet duct, and anupper surface; and a removable module having a bottom surface contactingthe upper surface of the constant flow pump, such that the modulefacilitates fluid communication between the active substance chamber andthe outlet duct.

Yet another aspect of the present invention is a method of implanting aninfusion pump. The method may include the steps of determining the needfor a variable or constant flow infusion pump, selecting, based upon thedetermining step, a pump housing and a module, the module selected froma variable flow module and a constant flow module, engaging a bottomsurface of the module with an upper surface of the housing to constructthe infusion pump, such that the restrictor module is in fluidcommunication with the housing, and implanting the infusion pump in thebody of a patient.

Yet another aspect of the present invention is an implantable infusionpump for dispensing an active substance at varying flow rates to apatient. The pump may include a constant flow pump having a housingdefining an upper surface, an active substance chamber, a propellantchamber separated from the active substance chamber by a first flexiblemembrane, an outlet duct having a catheter attached thereto, an exitopening in fluid communication with the active substance chamber and aentrance opening in fluid communication with the outlet duct. The pumpmay also include a removable module including a bottom surfacecontacting the upper surface of the constant flow pump, an entry formedin the bottom surface in fluid communication with the exit opening ofthe housing, an exit in fluid communication with the entrance opening ofthe housing, a needle portion having a longitudinally varying crosssection along its length disposed within a valve body, means forlongitudinally moving the needle portion within the valve body, a fixedflow restrictor in fluid communication between the entry of the moduleand the valve body of the module, and first and second pressure sensorslocated on either side of the fixed flow restrictor. Preferably, duringoperation of the pump system, a fluid dispelled from the activesubstance chamber by a force from the propellant chamber passes throughthe exit opening of the housing, through the entry of the module, intocontact with the first pressure sensor, through the fixed flowrestrictor, into contact with the second pressure sensor, through thevalve body of the module, through the exit of the module, through theentrance opening of the housing, through the outlet duct, and throughthe catheter.

Yet another aspect of the present invention is a method of monitoringthe amount of medicament dispensed from an implantable infusion pump. Inaccordance with one embodiment of this aspect, the method includes thesteps of providing a pump having the medicament disposed housed therein,dispensing at least some of the medicament from the pump at varyingactual flow rates, measuring the actual flow rate of the medicament fromthe pump at least two different times, storing information relating tothe actual flow rate and calculating the overall amount of medicamentdispensed based upon the information relating to the flow rate.

Another aspect of the present invention is a programmable module for usewith an implantable pump including a hermetic housing having acompletely sealed interior, the interior including a first pressuresensor, a second pressure sensor, an actuation mechanism, and aninterface in contact with the actuation mechanism, and a valve unitincluding a valve in contact with the interface. In other embodiments ofthis aspect, the hermetic housing includes an upper portion, a lowerportion, and a bracket. The valve unit may be disposed within a recessformed by the bracket. The actuation mechanism may include a motor andan offset cam. The interface may include a flexible membrane, whereoperation of the motor and offset cam causes the flexible membrane toflex. The valve may be a double sided needle valve, and the flexing ofthe flexible membrane causes translation of a stem of the double sidedneedle valve. The hermetic housing may be constructed of a metallicmaterial, including titanium. The valve unit may be constructed of apolymeric material, including PEEK. Portions of the first and secondpressure sensors may extend out of the hermetic housing, where theportion of the second pressure sensors extending out of the hermetichousing is in fluid communication with the valve unit. The valve unitmay further include first, second, and third openings, where one of theopenings is in communication with the second pressure sensor. Theinterior may further include at least one battery and a circuit board incommunication with the battery and the first and second pressuresensors. The hermetic housing may include a duct formed therethrough. Akit may also be provided including the programmable module discussedabove coupled with a constant flow pump.

Yet another aspect of the present invention is a programmable pumpsystem for dispensing an active substance at varying flow rates to apatient including a pump having an upper surface, an active substancechamber, a first opening in fluid communication with the activesubstance chamber and a second opening in fluid communication with acatheter, a hermetic housing attached to the pump including a firstpressure sensor in fluid communication with the active substancechamber, a second pressure sensor, and an actuator and a valve unitattached to the pump housing including a third opening in fluidcommunication with the first opening, a fourth opening in fluidcommunication with the second opening, a fifth opening in fluidcommunication with the second pressure sensor, a valve body, a valvestem disposed within the valve body and in contact with the actuator. Inother embodiments of this aspect, the pump may further include apropellant chamber separated from the active substance chamber by afirst flexible membrane. The valve may have a longitudinally varyingcross section along its length. The hermetic housing is completelysealed. During operation of the pump, a fluid dispelled from the activesubstance chamber may pass through the first opening, through the thirdopening, through the valve body of the module, through the fourthopening of the valve unit, through the second opening of the housing,and through the catheter. The pump housing may further include a sixthopening in fluid communication with the active substance chamber, andfluid dispelled from the active substance chamber passes through thesixth opening and into contact with the first pressure sensor. The valveunit may further include a seventh opening in fluid communication withthe second pressure sensor. The pump may further include a fixed flowresistor, where the fixed flow resistor includes a capillary. Fluiddispelled from the active substance chamber may pass through the fixedflow resistor prior to passing through the first opening. A cap may beattached to the pump to cover the hermetic housing and the valve unit.The actuator may include a motor and an offset cam. The hermetic housingmay further include an interface in contact with the actuator. Theinterface may be a flexible membrane where operation of the motor andoffset cam causes the flexible membrane to flex, the flexing causing thevalve to translate. The hermetic housing may further include a processorchip capable of processing pressure information from the first andsecond pressure sensors. The hermetic housing may further include anelectronic circuit board, the processor chip being mounted on theelectronic circuit board. An antenna may be provided for receivinginformation representative of a desired flow rate from an outsidesource. The antenna may be mounted on the valve unit.

A further aspect of the present invention is a method of refilling animplantable pump including inserting a refill device into theimplantable pump, transferring a fluid from the refill device to theimplantable pump and monitoring a pressure within the implantable pump,the pressure increasing upon transfer of the fluid from the refilldevice to the implantable pump. The inserting step may include utilizinga needle and the transferring step includes injecting the fluid from theneedle. The method may further include the step of piercing a septumwith the needle. The monitoring step may include receiving a pressurereading from a pressure sensor within the pump, and the monitoring stepmay be conducted wirelessly. The transferring and monitoring steps maybe conducted simultaneously, and the transferring step may includefilling a medication chamber of the pump. The pressure may be monitoredwithin the medication chamber, where a maximum pressure within themedication chamber is achieved upon completion of the refilling method.The method may further include the step of removing the refill device.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the subject matter of the presentinvention and the various advantages thereof can be realized byreference to the following detailed description in which reference ismade to the accompanying drawings in which:

FIG. 1 is a cross sectional front view of a reduced size implantablepump in accordance with one embodiment of the present invention.

FIG. 2 is a cross sectional bottom view of a portion of the reducedsized implantable pump shown in FIG. 1.

FIG. 3 is an enlarged view of an attachment area of the pump shown inFIG. 1.

FIG. 4 is a cross section front view of a reduced size implantable pumpin accordance with another embodiment of the present invention.

FIG. 5 is a cross section front view of a reduced size implantable pumpin accordance with another embodiment of the present invention.

FIG. 6 is a cross section front view of a reduced size implantable pumpin accordance with another embodiment of the present invention.

FIG. 7 is a cross sectional front view of an implantable constant flowpump for use in accordance with the present invention.

FIG. 8 is a cross sectional front view of another implantable constantflow pump for use in accordance with the present invention.

FIG. 9 is a cross sectional view of a variable flow resistor inaccordance with a first embodiment of the present invention having afilament located concentrically in a capillary.

FIG. 10 a is a longitudinal cross sectional view of the variable flowresistor of FIG. 9, in an initial position.

FIG. 10 b is a longitudinal cross sectional view of the variable flowresistor of FIG. 10 a, in an extended position.

FIG. 11 a is a cross sectional view of a variable flow resistor of thepresent invention having a filament located eccentrically in acapillary.

FIG. 11 b is a longitudinal cross sectional view of the variable flowresistor of FIG. 11 a, depicting the curvature of the capillary.

FIG. 12 a is a longitudinal cross sectional view of the variable flowresistor of FIG. 11 a, in an initial position.

FIG. 12 b is a longitudinal cross sectional view of the variable flowresistor of FIG. 12 a, in an extended position.

FIG. 13 is a longitudinal cross sectional view of another variable flowresistor in accordance with the present invention.

FIG. 14 is a longitudinal cross sectional view of another variable flowresistor in accordance with the present invention.

FIG. 15 is a cross sectional view of the driving assembly for use withthe flow resistor of FIG. 14.

FIG. 16 is a cross sectional view of a variable flow resistor inaccordance with a second embodiment of the present invention in a highresistance position.

FIG. 17 is a cross sectional view of the variable flow resistor of FIG.16 in a low resistance position.

FIG. 18 is a cross sectional view of a variable flow resistor inaccordance with a third embodiment of the present invention with aninsert centrally located.

FIG. 19 is a cross sectional view of a variable flow resistor inaccordance with a third embodiment of the present invention with aninsert eccentrically located.

FIG. 20 is a longitudinal cross sectional view of the variable flowresistor of FIG. 18.

FIG. 21 is a cross sectional view of the larger end of a variable flowresistor in accordance with a fourth embodiment of the present inventionwith an insert centrally located.

FIG. 22 is a cross sectional view of the larger end of a variable flowresistor in accordance with a fourth embodiment of the present inventionwith an insert eccentrically located.

FIG. 23 is a longitudinal cross sectional view of the variable flowresistor of FIG. 21.

FIG. 24 is a longitudinal cross sectional view of the variable flowresistor of FIG. 22.

FIG. 25 is a cross sectional view of a variable flow resistor inaccordance with a fifth embodiment of the present invention with aninsert centrally located.

FIG. 26 is a cross sectional view of a variable flow resistor inaccordance with a fifth embodiment of the present invention with aninsert eccentrically located.

FIG. 27 is a longitudinal cross sectional view of the variable flowresistor of FIG. 25.

FIG. 28 is a longitudinal cross sectional view of the variable flowresistor of FIG. 25.

FIG. 29 is a cross sectional view of an implantable pump in accordancewith another embodiment of the present invention.

FIG. 30 is a cross sectional view of the implantable pump shown in FIG.29, taken along a different portion thereof.

FIG. 31 is a partial top view of the implantable pump shown in FIG. 29.

FIG. 32 is a top perspective view of another embodiment implantable pumpof the present invention.

FIG. 33 is a cross sectional view of the pump depicted in FIG. 32.

FIG. 34 is another cross sectional view of the pump depicted in FIG. 32.

FIG. 35 is top perspective view of the pump depicted in FIG. 32, with afirst embodiment variable flow module attached thereto.

FIG. 36 is a cross sectional view of the pump and module depicted inFIG. 35.

FIG. 37 is another cross sectional view of the pump and module depictedin FIG. 35.

FIG. 38A is a top cross sectional view of the pump and module depictedin FIG. 35.

FIG. 38B is an enlarged top view of a differently configured offset camor extension for imparting movement to a valve.

FIGS. 39 a and 39 b are cross sectional views of a valve utilized in themodule of FIG. 35.

FIG. 40 is a top perspective view of the pump and module of FIG. 35,with certain portions of the module being transparent or removed forillustrative purposes.

FIG. 41 is a side perspective view of the pump and module of FIG. 35,with certain portion of the module being removed for illustrativepurposes.

FIG. 42 another cross sectional view of the pump and module of FIG. 35.

FIG. 43 is an enlarged version of FIG. 42, with certain portions shownas transparent for illustrative purposes.

FIG. 44 is a top perspective exploded view of the pump and module ofFIG. 35.

FIG. 45 is a bottom perspective exploded view of the pump and module ofFIG. 35.

FIG. 46 is a top perspective view of the pump and module of FIG. 46 withcertain portions of the module being removed for illustrative purposes.

FIG. 47 is a top view of the pump and module of FIG. 46 with attentionto an electronic board of the module.

FIG. 48 is an illustration of the electronic board of FIG. 46.

FIG. 49A is a block diagram illustrating the general operation of thepump and module of FIG. 35 in conjunction with a PC.

FIG. 49B is another block diagram illustrating the general operation ofthe pump and module of FIG. 35 in conjunction with a handheld device.

FIG. 50 is a perspective view of a constant flow module for use with animplantable pump.

FIG. 51 is a perspective view of the constant flow module of FIG. 50connected to the pump of FIG. 32.

FIG. 52 is a top perspective view of another embodiment implantable pumpof the present invention.

FIG. 53 is a side view of the pump of FIG. 52.

FIG. 54 is a side view of the pump of FIG. 52.

FIG. 55 is a rear view of the pump of FIG. 52.

FIG. 56 is a front view of the pump of FIG. 52.

FIG. 57 is a top view of the pump of FIG. 52.

FIG. 58 is a bottom view of the pump of FIG. 52.

FIG. 59 is a perspective view of the pump of FIG. 52, with a coverremoved therefrom.

FIG. 60 is a perspective view of the programmable module of the pump ofFIG. 52.

FIG. 61 is a top view of the programmable module of FIG. 60.

FIG. 62 is a bottom view of the programmable module of FIG. 60.

FIG. 63 is a perspective view of a hermetic housing of the programmablemodule of FIG. 60.

FIG. 64 is a top view of the hermetic housing of FIG. 63.

FIG. 65 is a bottom view of the hermetic housing of FIG. 63.

FIG. 66 is a top perspective view of an upper housing portion of thehermetic housing of FIG. 63.

FIG. 67 is a bottom perspective view of the upper housing portion ofFIG. 66.

FIG. 68 is a top perspective view of a lower housing portion of thehermetic housing of FIG. 63.

FIG. 69 is a bottom perspective view of the lower housing portion ofFIG. 68.

FIG. 70 is a perspective view of a bracket of the hermetic housing ofFIG. 63.

FIG. 71 is a perspective view of the hermetic housing of FIG. 63, withthe upper housing portion and the bracket removed therefrom.

FIG. 71A is an exploded perspective view of a motor, eccentric gear orcam and ball bearing arrangement.

FIG. 71B is an exploded perspective view of a motor and motor adjustmentplate assembly.

FIG. 72 is a similar view to that of FIG. 71, with additional componentsremoved from the hermetic housing of FIG. 63.

FIG. 73 is a top perspective view of a valve unit of the programmablemodule of FIG. 60.

FIG. 74 is a front perspective view of the valve unit of FIG. 73.

FIG. 75 is a side perspective view of the valve unit of FIG. 73.

FIG. 76 is a rear perspective view of the valve unit of FIG. 73.

FIG. 77 is a top view of the valve unit of FIG. 73.

FIG. 78 is another side perspective view of the valve unit of FIG. 73.

FIG. 79 is a bottom view of the valve unit of FIG. 73.

FIG. 80A is a similar view of the valve unit to that of FIG. 73, butwith certain portions shown in transparent.

FIG. 80B is a similar view of the valve unit to that of FIG. 77, butwith certain portions shown in transparent.

FIG. 80C is a similar view of the valve unit to that of FIG. 79, butwith certain portions shown in transparent.

FIG. 81A is a perspective view of a double-sided valve of the valve unitof FIG. 73.

FIG. 81B is an exploded view of the double-sided valve of FIG. 81A shownin conjunction with other portions of the valve unit.

FIG. 82 perspective view of the pump of FIG. 52, with the cover andprogrammable module removed therefrom.

FIG. 83 is a top view of the construct of FIG. 82.

FIG. 84 is a perspective view of the construct of FIG. 82, with an upperportion removed therefrom.

FIG. 85 is a perspective view of the construct of FIG. 82, with a lowerportion removed therefrom.

FIG. 86 is a cross-sectional view of the construct of FIG. 85 takenalong line A-A.

FIG. 87 is a cross-sectional view of the construct of FIG. 85 takenalong line B-B.

FIG. 88 is a cross-sectional view of the pump of FIG. 52 taken alongline C-C.

FIG. 89 is a cross-sectional view of the pump of FIG. 52 taken alongline D-D.

FIG. 90 is an exploded view of the construct shown in FIG. 82.

FIG. 91 is an exploded view of a propellant bag construct according tothe present invention.

DETAILED DESCRIPTION

In describing the preferred embodiments of the subject matterillustrated and to be described with respect to the drawings, specificterminology will be used for the sake of clarity. However, the inventionis not intended to be limited to any specific terms used herein, and itis to be understood that each specific term includes all technicalequivalents which operate in a similar manner to accomplish a similarpurpose.

Referring to the drawings, wherein like reference numerals refer to likeelements, there is shown in FIGS. 1 and 2, in accordance with variousembodiments of the present invention, a reduced size implantable pumpdesignated generally by reference numeral 1010. In a preferredembodiment, pump 1010 is a constant flow pump including a housing 1012,which further defines an interior having two chambers 1014 and 1016.Chambers 1014 and 1016 are preferably separated by a flexible membrane1018. It is noted that membrane 1018 may be of any design known in theart, for example, a membrane like that disclosed in commonly owned U.S.Pat. No. 5,814,019, the disclosure of which is hereby incorporated byreference herein. In a preferred embodiment, chamber 1014 is designedand configured to receive and house an active substance such as amedication fluid for the relief of pain, treatment of spasticity andneuro-mechanical deficiencies and the administration of chemotherapy,while chamber 1016 may contain a propellant that expands isobaricallyunder constant body heat. This expansion displaces member 1018 such thatthe medication fluid housed in chamber 1014 is dispensed into the bodyof the patient through an outlet catheter 1015 (best shown in FIG. 2).

The design and configuration of housing 1012 is such that manufacturingand assembly of pump 1010 is relatively easy. Housing 1012 furtherincludes separately manufactured top portion 1020, bottom portion 1022and locking portion 1024. It is noted that in certain preferredembodiments, housing 1012 defines a substantially circular pump 1010.However, the housing may ultimately be a pump of any shape. In additionto the above described elements, pump 1010 also preferably includesreplenishment port 1026 covered by a first septum 1028 that is in fluidcommunication with chamber 1014 through a channel 1029, an annular ringbolus port 1030 covered by a second septum 1032, and barium filledsilicone o-ring 1033. Each of these elements will be discussed furtherbelow.

Referring to both FIGS. 1 and 2, where FIG. 2 is a cross sectionalbottom view of locking portion 1024, the flow path of a medication fluidcontained within chamber 1014 is shown. Upon the expansion of propellantcontained within propellant chamber 1016 and the necessary displacementof membrane 1018, fluid contained in chamber 1014 is forced through anopening 1049 and into a cavity 1046, which will be further describedbelow. As shown in FIG. 2, cavity 1046 extends in a circular fashionaround pump 1010. Once in cavity 1046, the fluid may enter at any pointalong the length of a filter capillary 1072. Essentially, filtercapillary 1072 is a well known type filter that allows for fluid toenter into its inner fluid path through permutation or the like. Thus,once a certain amount of fluid builds up within cavity 1046, it iscapable of entering into filter 1072. This filter is preferably fixedand sealed in position by drops of glue or other adhesive located at1070 and 1074. The fluid then travels through filter capillary 1072until it exits into a resistor 1076. This resistor is preferably a longtube having a relatively small diameter, so as to dictate the maximumflow rate that may be achieved therethrough. In other words, the smallerthe diameter of resistor 1076, the slower the flow rate of fluidtraveling therethrough. Nevertheless, as more fully discussed below,resistor 1076 may be many different types of designs. The fluid withinresistor 1076 then continues to an opening 1078 for a bridge 1080, whichessentially allows resistor 1076 to cross over bolus port 1030.Thereafter, the fluid may continue through resistor 1076 and ultimatelyout catheter 1015. Epoxy or another suitable adhesive or sealant may beutilized to seal end 1070, end 1074 and opening 1078. Thus, fluid incavity 1046 may only follow the path outlined above.

It is noted that FIG. 2 also depicts the flow path that fluid introducedthrough a bolus injection may take. Fluid may be injected into bolusport 1030 through the use of a device suitable for piercing septum 1032,such as a needle. Once in port 1030, which extends around pump 1010,fluid may enter a channel 1082. This channel extends at least partiallyaround the above mentioned bridge 1080, and allows fluid injected intobolus port 1030 to ultimately exit catheter 1015 without passing throughany portion of resistor 1076. As shown in FIG. 2, regardless of the paththe fluid takes, it ultimately ends up in a passage 1084 just prior tocatheter 1015. Thus, fluid coming from chamber 1014 may have one flowrate, while fluid directly injected into port 1030 may have a differentflow rate, the latter preferably being greater.

The assembly of pump 1010 will now be discussed. It is noted that eachof the individual elements/components of pump 1010 may be individuallymanufactured and thereafter assembled by hand or by another process,such as an automated process. As an initial step, top portion 1020 andbottom portion 1022 are placed or sandwiched together so as to capturemembrane 1018 therebetween in an attachment area 1034 for fixablyretaining same. As more clearly shown in the enlarged view of FIG. 3,attachment area 1034 comprises a projection 1036 located on bottomportion 1022, a depression 1038 located on top portion 1020, and acavity 1040 formed through the cooperation of the two portions. Inoperation, the step of sandwiching together portions 1020 and 1022, withmembrane 1018 disposed therebetween, causes projection 1036 to be forcedinto depression 1038. The portion of membrane 1018 disposed therebetweenis thus also forced into depression 1038 by projection 1036. This causesa crimp-like connection, which fixably attaches and retains membrane1018 within housing 1012. As shown in FIG. 3, membrane 1018 may consistof multiple layers, of which all are preferably “crimped” during theattachment process. Prior to pressing together portions 1020 and 1022, alayer of epoxy or other adhesive may be inserted into cavity 1040. Insuch embodiments that employ the use of an adhesive, the design maycause portions 1020 and 1022 to become fixably attached to one anotherupon the sandwiching of same. Further, the use of an adhesive withincavity 1040 may also aid in the fixation of membrane 1018 between thetwo portions. The epoxy or other adhesive may be placed into the cavityportion formed on either portion 1020 or portion 1022, prior to thesandwiching step.

Prior or subsequent to the assembly of top portion 1020 together withbottom portion 1022, o-ring 1033 or the like may be placed into aring-shaped cavity formed in top portion 1022. In certain preferredembodiments, o-ring 1033 is a barium filled silicone o-ring, and isdisposed around the area defining replenishment port 1026. Such ano-ring design allows for the area defining replenishment port 1026 to beilluminated under certain scanning processes, such as X-rays. As pump1010 is implanted within the human body, locating port 1026, in order torefill the pump with medicament or the like, may be difficult. Providinga barium filled o-ring 1033, which essentially outlines the area of port1026, allows for a doctor to easily locate the desired area under wellknown scanning processes. Other structures may be utilized, in whichsame also show up on different scans. The placement of o-ring 1033 ispreferably accomplished by pressing the o-ring into an undersizedchannel that retains the o-ring, thereafter.

With o-ring 1033 preferably in place, locking portion 1024 is nextattached to the other portions. It is noted that prior to attachingportion 1024, first septum 1028 should be inserted into locking portion1024. Preferably, first septum 1028 is slid into a complimentary cavityformed in portion 1024, such that it remains within absent a forceacting upon same. As first septum 1028 is designed to be capturedbetween locking portion 1024 and top portion 1020, the septum should beplaced prior to the attachment of locking portion 1024. In addition, asmentioned above, locking portion 1024 may include a second septum 1032for covering bolus port 1030. In certain preferred embodiments, as shownin FIG. 1, second septum 1032 is ring shaped, and is pressed intolocking portion 1024 in a similar fashion to that discussed above withrelation to the placement of o-ring 1033. This may be done prior orsubsequent to the attachment of locking portion 1024 to the otherportions.

With regard to the attachment step, locking portion 1024 preferablyincludes a threaded area 1042 for cooperating with a threaded extension1044. In operation, locking portion 1024 is merely screwed intoengagement with bottom portion 1022. This necessarily causes top portion1020, which is disposed between the two other portions, to be retainedtherebetween. In other words, the screw attachment of locking portion1024 with bottom portion 1022 not only causes such portions to befixably attached to one another, but also causes top portion 1020 to befixably retained therebetween. It is noted that, depending upon howtight locking portion 1024 is screwed into 1022, portions 1020 and 1022may be further pressed together, thereby increasing the fixation ofmembrane 1018 therebetween. Thus, pump 1010 is designed so that minimalconnection steps are performed in order to cause all of the componentsthereof to be retained together. It is further noted that, in additionto the above discussed screw connection of portions 1022 and 1024, otherattachment means may be utilized. For example, such portions may be snapfit together or fixed utilizing an adhesive. Finally, locking portion1024 may be configured so as to form cavity 1046 between itself and topportion 1020. This cavity may be designed so as to allow for theinjection of adhesive therein, thus increasing the level of fixationbetween the different portions of housing 1012. Additionally, cavity1046 may house a flow resistor or the like, as will be more fullydiscussed below.

As set forth above, pump 1010 is configured and dimensioned to berelatively simplistic in both manufacture and assembly. However, pump1010 is also configured and dimensioned so as to employ a significantlyreduced overall size, while still providing for a useful amount ofmedicament and propellant to be housed therein. In the preferredembodiments depicted in the figures, top portion 1020 of pump 1010includes an interior surface 1047 having an undulating or convolutedshape. More particularly, surface 1047 includes a convex central portionflanked by two concave portions. This configuration allows for thecentrally located replenishment port 1026 and cooperating septum 1028 tobe situated in a lower position with respect to the remainder of pump1010. At the same time, the aforementioned flanking concave portionsallow for the overall volume of chambers 1014 and 1016 to remainsubstantially the same as a pump employing an interior surface havingone constant concave portion or the like. In other words, the flankingconcave portions make up for the volume lost in situating port 1026 andcooperating septum 1028 in a lower position. Membrane 1018 is alsopreferably configured so as to have an initial undulating shape forcooperation with interior surface 1047. Thus, with no medicament orother fluid located within chamber 1014, membrane 1018 preferably restsagainst surface 1047. However, upon injection of fluid into chamber1014, membrane 1018 adapts to the position shown in FIG. 1.

FIG. 4 depicts another reduced sized implantable pump designated byreference numeral 1110. As shown in the figure, pump 1110 includesseveral elements which are similar in structure and function to that ofpump 1010. These elements are labeled with like references numeralswithin the 1100 series of numbers. For example, membrane 1118 is similarto the above described membrane 1018. In addition, pump 1110 operates ina similar fashion to that of pump 1010. Nevertheless, pump 1110 doesinclude certain additional elements, as well as elements employingdifferent constructions. Most notably, pump 1110 includes an additionalcomponent, namely septum retaining member 1125. This member ispreferably adapted to be screwed into top portion 1120. Pump 1110 alsoincludes a bottom o-ring 1150, but does not include a barium filledo-ring.

The assembly of pump 1110 also differs from that of pump 1010. Asbriefly mentioned above, initially, septum retaining member 1125 isfirst screwed into top portion 1120 in order to retain previously placedseptum 1128 in place. Like the above described assembly of pump 1010,the assembly of pump 1110 then includes the step of sandwiching togetherportions 1120 and 1122, where membrane 1118 is likewise capturedtherebetween in attachment area 1134. However, in this embodiment,locking portion 1124 is adapted to engage top portion 1120, so that itis positioned on the bottom side of pump 1110. As shown in FIG. 4, topportion 1120 includes a threaded extension 1152 to cooperate and engagewith threaded area 1142 of locking portion 1124. The screw connectionbetween the two portions is similarly achieved. However, bottom o-ring1150 is preferably situated between locking portion 1124 and bottomportion 1122. This o-ring both increases the force exerted on bottomportion 1122 by locking portion 1124, and also causes housing 1112 toretain a smooth exterior surface. The latter is important in implantingthe pump within a patient, as rough or jagged surfaces may cause damageto tissue abutting the pump. Finally, it is noted that second septum1132 may be pressed into top portion 1120, at any point during theassembly.

FIG. 5 depicts another reduced sized implantable pump designated byreference numeral 1210. As shown in that figure, pump 1210 includesseveral elements which are similar in structure and function to that ofpumps 1010 and 1110. Once again, these elements are labeled with likereference numerals within the 1200 series of numbers. Nevertheless, pump1210 does include certain additional elements, as well as elementsemploying different constructions. For example, like pump 1110, pump1210 includes a septum retaining member 1225. Similarly, like pump 1010,pump 1210 utilizes a top mounting locking portion 1224, although it hasa different construction.

The assembly of pump 1210 differs from that of the above discussed pumps1010 and 1110. Like pump 1110, septum retaining member 1225 is firstscrewed into top portion 1220, in order to retain previously placedseptum 1228 in place. Next, portions 1120 and 1222 are sandwichedtogether, thus capturing member 1218 within attachment 1234. Finally,locking portion 1224 is screwed into engagement with bottom portion1222. Like the design of pump 1010, locking portion 1224 includes athreaded area 1242 which engages a threaded extension 1244 of bottomportion 1222. In addition to completing the assembly of pump 1210 bycapturing bottom portion 1222 and forcing top portion 1220 towardsbottom portion 1222, locking portion 1224 is configured and dimensionedin this embodiment to also capture second septum 1232. As shown in FIG.5, locking portion 1224 includes a concave section 1254 for engagingseptum 1232 upon the full engagement of portions 1222 and 1224.

Yet another embodiment reduced sized pump 1310 is shown in FIG. 6. Likethose pumps discussed above, pump 1310 preferably includes severalelements which are similar in structure and function, and are thuslabeled with like reference numerals within the 1300 series of numbers.Essentially, pump 1310 is akin to the configuration set forth in pump1210. However, there are two main distinctions, namely, the cooperationof locking portion 1324 and portions 1320 and 1322, and the inclusion ofa channel 1362 between locking portion 1324 and top portion 1320. In theembodiment depicted in FIG. 6, it is noted that locking portion 1324includes a threaded extension 1356, which cooperate and engage threadedareas 1358 and 1360 of portions 1320 and 1322, respectively.Furthermore, locking portion 1324 preferably includes a channel 1362formed therein. This channel may be adapted to cooperate with any of thechambers and/or ports discussed above. Additionally, channel 1362 mayhouse other elements, such as a flow resistor or the like, which will bediscussed more fully below.

A second aspect of the present invention relates to providing a constantflow type implantable pump with infinitely variable flow capabilities. Amentioned above, such a construction may be beneficial to patientsrequiring more or less medication to be delivered by an implantablepump. While the different embodiments of this second aspect of thepresent invention may indeed be sized and configured to be utilized withany constant flow type implantable pump, preferred pumps will bedescribed herein. In one preferred pump, as shown in FIG. 7 of thepresent application, the basic implantable pump design is designated asreference numeral 20. Pump 20 includes a housing 22 defining an interiorhaving two chambers 24 and 26. Chambers 24 and 26 are separated by aflexible membrane 28. Chamber 24 is designed to receive and house theactive substance such as a medication fluid for the relief of pain,treatment of spasticity and neuro-mechanical deficiencies and theadministration of chemotherapy, while chamber 26 may contain apropellant that expands isobarically under body heat. This expansiondisplaces membrane 28 such that the medication fluid housed in chamber24 is dispensed into the body of the patient through the path defined byan outlet opening 30, a resistor 32, an outlet duct 34 and ultimately anoutlet catheter 36.

Resistor 32 provides a connection between chamber 24 and outlet duct 34.Thus, as mentioned above, a medication fluid flowing from chamber 24 tooutlet catheter 36 must necessarily pass through resistor 32. Thisresistor allows for the control of the flow rate of the medicationfluid, such that the flow rate is capable of being varied. Resistor 32may be configured differently in many different embodiments, some ofwhich are discussed below in the detailed description of the presentinvention. Essentially, resistor 32 defines a passageway for the flow ofthe medication fluid, where the passageway may be altered to therebyalter the flow rate of the medication fluid.

Implantable pump 20 also includes a replenishment port 38 covered by afirst septum 40. Septum 40 can be pierced by an injection needle (suchas needle 42 shown in FIG. 7) and, upon removal of such needle, iscapable of automatically resealing itself. Septa of this type are wellknown to those of ordinary skill in the art. As implantable pump 20 isdesigned to medicate a patient over a limited period of time,replenishment port 38 is utilized for replenishing chamber 24 when emptyor near empty. In operation, a physician or other medical professionalinserts an injection needle 42 into an area of a patient's body wherepump 20 is located, such that it may pierce septum 40. Thereafter,operation of the needle causes injection of the solution from the needleto pass into port 38, through passage 44, and into chamber 24. It isnoted that the particular dimension and/or the patient's need mayrequire such a process to be repeated at given intervals, for example,monthly, weekly, etc.

In addition to replenishment port 38, pump 20 also includes an annularring bolus port 46 covered by a second septum 48. Essentially, this portallows for direct introduction of a solution into outlet catheter 36 andto the specific target area of the body. This port is particularlyuseful when a patient requires additional or stronger medication, suchas a single bolus injection, and/or when it is desired to test the flowpath of catheter 36. Such an injection is performed in a similar fashionto the above discussed injection into replenishment port 38. However, aninjection into bolus port 46 bypasses passage 44, chamber 24 andresistor 32, and provides direct access to catheter 36. It is alsocontemplated to utilize bolus port 46 to withdraw fluid from the body.For example, where pump 20 is situated within the body such thatcatheter 36 extends to the vertebral portion of the spinal column, aneedle with a syringe connected may be inserted into bolus portion 46and operated to pull spinal fluid through catheter 36 and into thesyringe.

In certain embodiments, septum 40 and septum 48 may be situated so thatonly specifically designed injection needles may be used to inject intothe respective ports. For example, as is also shown in FIG. 7, septum 48may be situated relatively close to the bottom of port 46 and septum 40may be situated a greater distance away from the bottom of port 38. Inthis embodiment, injection needle 42 is provided with an injection eye43, which is located above the tip of needle 42. Alternatively,injection needle 50 is provided with an injection eye 51 located at ornear its tip. This arrangement prevents needle 42, which is typicallyutilized for replenishing chamber 24 with a long term supply ofmedication fluid, from being inadvertently used to inject its contentsinto bolus port 46. As is shown on the left side depiction of bolus port46, needle 42 would have its eye 43 blocked by septum 48 if the needleis inadvertently inserted into this port. Needle 50, on the other hand,would be capable of injecting into port 46 because of the lower locationof its eye 51. This is an important safety feature, as direct injectionof a long term supply of medication fluid into port 46 could bedangerous. It is noted that needle 50 is also capable of injecting asolution into replenishment port 38, however, the same concerns(i.e.—over-medication) do not exist with respect to the filling ofchamber 24, and as such medication housed in the chamber is slowlyreleased. While this is one example of a possible safety feature withregard to the injection of materials into the pump, it is envisionedthat other safety precautions may be utilized. For example, U.S. Pat.No. 5,575,770, the disclosure of which is hereby incorporated byreference herein, teaches a similar multiple injection needle systemwith additional valve protection. It is noted that such a safety needlesystem may be employed with regard to any of the various implantablepump embodiments disclosed herein. One of ordinary skill in the artwould recognize the modifications required to utilize such a safetyfeature in the other discussed pump designs.

In other embodiments, the basic implantable pump design of theaforementioned '873 patent may also be utilized. As is discussed in itsspecification and shown in FIG. 8 of the present application, the '873patent discloses a housing made up of two parts 1, 2 and an interiorhaving two chambers 4, 5, which are separated by a flexible membrane 3.Chamber 4 is designed to receive and house the medication fluid, whilechamber 5 may contain a propellant which, like that discussed in theabove description of pump 20, expands isobarically under body heat. Thisexpansion displaces membrane 3 such that the medication fluid housed inchamber 4 is dispensed into the body of the patient through the pathdefined by an outlet opening 6, an outlet reducing means 7 andultimately an outlet catheter 8. It is noted that reducing means 7 ispreferably a tube winding that wraps around part 1 of the housing. Theresistor of the present invention, in certain embodiments, is preferablylocated at or near outlet opening 6. This will be discussed more fullybelow.

Prior to reaching outlet catheter 8, the medication fluid is introducedinto a chamber 9 which is provided annularly on part 1 of the housing.Chamber 9 is sealed at its upper side by a ring or septum 10, which canbe pierced by an injection needle and which automatically reseals uponwithdrawal of the needle. This chamber is similar to the above discussedbolus port 46 of pump 20. In addition to allowing medication fluid fromchamber 4 to pass into outlet catheter 8, chamber 9 also allows thedirect injection of a solution into outlet catheter 8, the importance ofwhich is discussed above. The aforementioned outlet reducing means 7prevents a solution injected into the bolus port from flowing intochamber 4. In a similar fashion, when need be, chamber 4 may bereplenished via a further septum 12. Once again an injection needle maybe utilized for this purpose.

While two basic designs of implantable pumps are described above, it isnoted that other designs may include different or additional elements.Similarly, while the above description teaches two implantable pumpsthat may be utilized in accordance with the present invention, otherimplantable pump designs are also capable of being utilized. Forexample, U.S. Pat. Nos. 5,085,656, 5,336,194, 5,722,957, 5,814,019,5,766,150, 5,836,915 and 6,730,060, the disclosures of which are allhereby incorporated by reference herein, may be employed in accordancewith the present invention. In addition, one specific embodiment will bediscussed below.

As mentioned above, the capability of varying the flow rate of animplantable pump is desired. In the above discussed constant flow pumps,the flow rate of the medication fluid depends upon the pump pressure,the pressure at the end of the catheter and the hydraulic resistance ofany of the capillaries or other passages that the medication fluid musttravel through. With regard to the resistance of the capillaries, suchresistance depends upon the geometry of the capillary itself, as well asthe viscosity of the medication fluid. This viscosity, as well as thepump pressure, may both be influenced by body temperature. As such, oneinstance in which it is desired to control the flow rate of the pumpexists if the patient develops a fever because the flow rate of theinfusion device may be affected in an undesired way.

Another example of when the variable flow rate of the implantable pumpis desired relates to the condition or active status of the patient. Forexample, especially in the case where painkillers are beingadministered, it may be advantageous to deliver less medication duringthe nighttime hours, when the patient is sleeping. Additionally, asdiscussed above, it may be desirable to be able to increase the dosageof such painkillers or the like when the patient's symptoms worsen.Increasing of the flow rate of the medication fluid may be necessary inorder to diminish the patient's pain level. In accordance with thepresent invention, the aforementioned resistor 32 is useful foradjusting the flow rate in order to counteract undesirable flow ratechanges due to body temperature changes, and to allow for desiredadjustments of flow rate to treat heightened or worsened symptoms.

In a first embodiment this adjustment of flow rate is realized byadjusting the cross-sectional geometry of an article of the resistor. Itis noted that the first embodiment will be discussed with respect topump 20; however, it may be utilized in combination with any implantablepump. As shown in FIGS. 9-15, in accordance with this first embodiment,resistor 32 includes an elastic and resilient filament 52 situated in aresistor capillary 54, where resistor capillary 54 provides a connectionbetween outlet opening 30 and outlet capillary 34. Capillary 54 may besituated so as to constitute substantially the entire outlet capillary34, or may only be a portion thereof. Essentially, capillary 54 needonly require the aforementioned medication fluid to pass therethrough,and thus, may be any length suitable for use in varying the flow rate.

FIGS. 9, 10 a and 10 b show a first example of the first embodimentresistor 32, where elastic filament 52 is located concentrically inresistor capillary 54. This configuration forms a ring-shaped flowchannel 56 through which fluid flows in a direction shown by arrow F. Asis best shown in FIG. 10 a, filament 52 includes a first end 58 attachedto a stationary attachment 60, and a second end 62 attached to a movableattachment 64. Resistor 32 also has an effective length L extendingbetween capillary entrance 66 to exit 68, and an initial diameter D1(i.e.—2 times its radius R1). Additionally, capillary 54 has a diameterD3 (i.e.—2 times its radius R3). This will be similar throughout in thevarious other capillaries discussed herein.

In this example, movable attachment 64 is capable of moving in theopposite longitudinal directions shown by arrows A and B, whileattachment 60 remains stationary. In operation, movement of attachment64 in the direction of arrow B increases the distance betweenattachments 62 and 64 and also results in the decrease of the initialdiameter D1 to a lesser diameter D2 (i.e.—2 times its lesser radius R2).This is best shown in FIG. 10 b. The decrease of the diameter offilament 52 from D1 to D2 increases the size of channel 56 and thusnecessarily decreases the hydraulic resistance in capillary 54.Oppositely, movement of attachment 64 in the direction of arrow Areturns filament 52 to the position shown in FIG. 10 a, and increasesthe hydraulic resistance in capillary 54. A filament of this type may beconstructed of silicone rubber, or other suitable polymer materials forproviding the required elasticity and resiliency so as to return to itsoriginal shape and size after being deformed by stretching. Similarly,although filament 52 is shown in the figures as having a substantiallycircular cross section, it is envisioned that filaments having othercross sections may be utilized, for example, polygonal, oval, square andthe like.

As the inner diameter of capillary 54 is typically very small (on theorder of several thousands of millimeters), it is often difficult tolocate filament 52 directly in the center of the capillary. FIGS. 11 a,11 b, 12 a and 12 b depict a second example where elastic filament 52touches the inner wall of capillary 54 (i.e.—an eccentric position).This eccentrically placed filament 52 creates a sickle-shaped flowchannel 56, as opposed to the ring-shaped flow channel of the firstexample. This second example also differs from the first examplediscussed above, in that both ends 58, 62 of filament 52 are attached tomovable attachments 60, 64, respectively. This is useful, as inoperation, one movable attachment (or the mechanism moving it) may fail.The two movable attachment design provides a failsafe, thereby allowingfilament 52 to be stretched through the movement of the non-failingattachment. Attachment 64 is still capable of moving in the directiondepicted by arrows A and B and attachment 60 is capable of moving in thedirection depicted by arrows A′ and B′.

In operation, movement of either of attachments 60, in the directions B′and B, respectively, decreases the diameter D1 to a lesser diameter D2(once again, these diameters refer to two times the radii R1 and R2,respectively). This position is best shown in FIG. 12 b. Like that ofthe above discussed first example, this decrease in the diameter offilament 52 from D1 to D2 increases the size of channel 56 and thusnecessarily decreases the hydraulic resistance in capillary 54.Oppositely, movement of either of attachments 60, 64 in the direction ofarrows A′ and A, respectively, returns filament 52 to the position shownin FIG. 12 a, and increases the hydraulic resistance in capillary 54.

Attachment 64 in the first example, and attachments 60, 64 in the secondexample may be moved by any means known to those of ordinary skill inthe art. For example, it is well known to utilize motors such asmicro-motors, magnets, or other hydraulic, electrical or mechanicalactuators. One example of a suitable motor assembly is sold under thedesignation X15G by Elliptec Resonant Actuator of Dortmund, Germany.

In accordance with the present invention, it is known to design acapillary with a circular lumen defined by a rigid wall. Essentially,this type of apparatus is a hollow tube having a flow therethrough(i.e.—the present design without filament 52). For such a design, theflow rate can be calculated using the well-known Hagen-PoisseuilleEquation:V=(pR24)/(8L)

Where:

V=flow rate

p=pressure difference between entrance 66 and exit 68 of capillary 54.

=viscosity of fluid.

L=effective length L of resistor 32.

R2=radius of resistor capillary 54 (see in FIG. 9).

As shown in the above equation, small changes in the diameter of acapillary have a profound effect on the flow rate. However, themodification of the R2 dimension is often technically very difficult torealize. Thus, as discussed above, the design of this first embodimentof the present invention includes implementing elastic filament 52 intoresistor capillary 54, as discussed above. For the first example of thefirst embodiment (i.e.—concentrically located filament 52), thefollowing equation may be utilized in determining the flow rate of thisdesign:V=[(p)(R2−R1)3(R2+R1)]/(8L)

Where:

V=flow rate

p=pressure difference between entrance 66 and exit 68 of capillary 54.

=viscosity of fluid.

L=effective length L of resistor 32.

R1=radius of filament 52 (see in FIG. 9).

R2=radius of resistor capillary 54 (see in FIG. 9).

Alternatively, for the second example of the first embodiment(i.e.—eccentrically located filament 52), the following equation may beutilized in determining the flow rate of this design:V=[(p)(R2−R1)3(R2+R1)2.5]/(8L)

Where:

V=flow rate

p=pressure difference between entrance 66 and exit 68 of capillary 54.

=viscosity of fluid.

L=effective length L of resistor 32.

R1=radius of filament 52 (see in FIG. 9).

R2=radius of resistor capillary 54 (see in FIG. 9).

All three of the above equations are well known in the field of fluiddynamics. Further, while the effective length L of resistor 32, as bestshown in FIGS. 10 a and 12 a, corresponds to the length of capillary 54,it is noted that the effective length more specifically relates to thelength of capillary 54 in which filament 52 resides. Therefore, theeffective length L, for use in the above equations, may be less than thelength of capillary 54 if filament 52 has a length less than the lengthof capillary 54. It is noted that these equations apply to the use ofcapillaries and filaments having circular cross sections. Otherembodiments may utilize differently shaped capillaries and filaments.For these embodiments, separate equations must be utilized.

As is clearly shown by the second equation, situating filament 52 in theoffset position with relation to the center of capillary 54 of, as shownin FIG. 11 a, allows the flow rate to be changed by a factor of 2.5.Therefore, for applications where it is desired to vary the flow rate bysuch a ratio, it is possible to merely move filament 52 from a centralposition taught in the first example (as shown in FIG. 9) to theeccentric position taught in the second example (as shown in FIG. 11 a).However, often times, it is typically desired to vary the flow rate by afactor of 25 or more. In order to achieve such a flow rate change, onemay utilize an elastic filament 52 as discussed above, situated in anoffset position. Typically, to ensure that filament 52 remains in theoffset position, a curved capillary 54 is utilized. As shown in FIG. 11b, filament 52 remains eccentrically placed within capillary 54 becauseof the curvature of the capillary. As filament 52 is generally elasticand resilient, it easily conforms to any curvature of capillary 54.

A realistic range for the change in diameter of elastic filament 52 isapproximately from its original size to about seventy percent of itsoriginal size (i.e.—a 1 to 0.7 ratio). Calculations have been carriedout using the above equation relating to the eccentrically positionedfilament 52. For example, with the initial radius R1 of filament 52being approximately eighty percent (80%) of the radius R2 of capillary54 (i.e.—a 0.8 to 1 ratio) and the maximal elongation of filament 52giving a radius R3 that is approximately fifty six percent (56%) of theradius R2 of capillary 54 (i.e.—a 0.56 to 1 ratio), it was calculatedthe ratio of flow rate between the non-elongated state and the maximalelongated state is approximately 9.20 to 1. With the initial radius R1of filament 52 being approximately eighty five percent (85%) of theradius R2 of capillary 54 (i.e.—a 0.85 to 1 ratio) and the maximalelongation of filament 52 giving a radius R3 that is approximately fiftynine point five percent (59.5%) of the radius R2 of capillary 54 (i.e.—a0.595 to 1 ratio), it was calculated the ratio of flow rate between thenon-elongated state and the maximal elongated state is approximately17.00 to 1. Finally, with the initial radius R1 of filament 52 beingapproximately ninety percent (90%) of the radius R2 of capillary 54(i.e.—a 0.9 to 1 ratio) and the maximal elongation of filament 52 givinga radius R3 that is approximately sixty three percent (63%) of theradius R2 of capillary 54 (i.e.—a 0.63 to 1 ratio), it was calculatedthe ratio of flow rate between the non-elongated state and the maximalelongated state is approximately 43.46 to 1. Thus, using a filament 52having a radius R1 between approximately eighty five percent (85%) andninety percent (90%) of the total radius R2 of capillary 54, wouldresult in a flow rate variation of approximately 25. From the foregoing,one can calculate the desired flow rate variation based on the knowngeometry of the flow resistor.

A third example of the first embodiment of the present invention isshown in FIG. 13. This example includes a capillary 154 that is dividedinto two sectors by a center wall 155. Fluid is capable of flowingthrough capillary 154 by entering through entrance 166 and exitingthrough exit 168, as depicted by fluid flow arrow F. An elastic filament152 is fixed at its ends by fixation points 160 and 164, and is wrappedaround a magnetic element 170 at the approximate central portion offilament 152. Repulsive magnetic forces are transmitted to magneticelement 170 by a corresponding magnetic counterpart 172, having asimilar polarity. Thus, movement of counterpart 172 results in the likemovement of element 170. Counterpart 172 may be located in ahermetically sealed housing 174, or the like. Movement of the magneticelement in a direction indicated by arrow B will, as in the abovediscussed examples, cause the diameter of filament 152 to shrink,thereby allowing for the increase in flow rate. Similarly, movement ofelement 170 in the direction indicated by arrow A will decrease the flowrate. It is noted that this two sector design includes two capillary andfilament relationships for use in varying the flow rate. As such, whereboth the capillary and the filament have circular cross sections, twoseparate calculations in accordance with the above discussed equations,must be conducted to determine the overall hydraulic resistance providedby the system.

Further, in accordance with this third example of the first embodiment,it is envisioned that magnetic element 170 and magnetic counterpart 172may be oppositely polarized, such that they are attracted to oneanother. In this type of design, moving counterpart 172 in a directioncloser to element 170 would cause the attraction between them to begreater. Thus, if counterpart 172 is located below element 170 (asopposed to that shown in FIG. 13), movement of counterpart 172 towardselement 170 would increase the magnetic attractive force between the twocomponents and necessarily cause the movement of element 170 in thedirection indicated by arrow B. As discussed above, this lengthensfilament 152, while at the same time decreasing its diameter. Thus, thiswould constitute one alternate design. Similarly, it is possible toprovide a single magnetic component with a corresponding metalliccomponent, rather than the above discussed two magnet configuration.Clearly, as is well understood, such components would be attracted toone another. Therefore, operation of this magnet/metal configurationwould operate in a like manner to the above discussed opposite polaritymagnetic configuration. However, it is to be understood that variousconfigurations are envisioned depending upon the polarity of themagnetic components and/or the situation of the metallic element and itscorresponding magnetic element. For example, filament 152 may be wrappedaround a metallic element, with a magnetic component located in housing174 or vice versa.

A fourth example of the first embodiment of the present invention isshown in FIG. 14. This example includes an elastic filament 252 that isfixed at one end by attachment 260 and wrapped around axle 276 on theother. Once again, fluid enters capillary 254 at entrance 266, and exitsat exit 268. Fluid flow direction is once again indicated by arrow F.Rotation of axle 276, in a direction depicted by arrow W(i.e.—counter-clockwise), causes filament 252 to lengthen, while itsdiameter reduces. This, in turn, increases the possible flow ratethrough capillary 254. Alternatively, rotation of axle 276 in aclockwise direction causes the opposite effect. As previously mentioned,if filament 252 and filament 254 have circular cross sections, the aboveequations may be utilized in calculating the hydraulic resistance of thesystem. Axle 276 may be driven directly by a micro motor, via areduction gear drive assembly 280 as shown in FIG. 15.

While other means may be utilized for driving axle 276, the followingsets forth a discussion of the aforementioned reduction gear driveassembly 280. As shown in FIG. 15, assembly 280 presents a solution forthe transfer of rotational motion from hermetic enclosure 274 to axle276. Assembly 280 includes a motor 282 that is augmented by a gear drive284 and transferred to disc 286. The disc includes a shaft 288 which ispreferably positioned at an angle which is less than ninety degreerelative to the plane of disc 286. Shaft 288 extends into cylindricalportion 290 of hermetic enclosure 274. Further, shaft 288 is supportedvia bearings 292 within cylindrical portion 290. Finally, cylindricalportion 290 is connected to enclosure 274 by an elastic connection 294and is capable of transmitting forces via pusher plate 296 to rotateaxle 276. Essentially, the offset nature of the connections between disc286 and shaft 288, and portion 290 and plate 296, coupled with theelastic nature of the connection between enclosure 274 and portion 290allows for the rotation of axle 276. It is noted that operation of themotor in different directions causes the rotation of the axle in theclockwise or counter-clockwise direction.

Gear drive assembly 280 is useful for allowing a relatively small orweak motor to drive axle 276. Providing a gear assembly to betterutilize a motor is well known. However, any known gear assembly,suitable for use with the present invention, may be employed. Further,it is also contemplated that a suitable motor may be employed that maybe capable of directly rotating axle 276. Essentially, in a design likethis, axle 276 may be a continuation of the drive shaft of the motor.

Any of the examples set forth in the discussion relating to this firstembodiment may include different, additional or fewer elements. Suchrevisions will be understood by those of ordinary skill in the art. Forexample, it is envisioned that the various elastic filaments, whileshown in the figures having a substantially circular cross section, mayinclude any shaped cross section. Similarly, although shown assubstantially straight, the above may be utilized in conjunction withcurved capillaries. Additionally, it is to be understood that theinventions set forth in the first embodiment may be utilized with anyknown implantable pump. The particular pump design may require the useof a resistor that is particularly configured and dimensioned to operatewith the pump. Such design requirements are evident to those of ordinaryskill in the art.

In a second embodiment the adjustment of flow rate is realized byproviding a pair of threaded matched cylinders for use as resistor 32.Once again, the second embodiment will be discussed with respect to pump20; however, it may be utilized in combination with any implantablepump. As shown in FIGS. 16 and 17, in accordance with this secondembodiment, resistor 32 includes a first threaded member 302 having ahollow interior 304 and a threaded exterior 306. First threaded memberis disposed in second threaded member 308, which is an oppositelyconfigured hollow member having a threaded interior surface 310 and aclosed end 312. The threaded cooperation between first and secondthreaded members 302 and 308 allows for the first member to be disposedwithin the second member at varying levels, therefore, allowing fordifferent overlaps of the two members. For example, FIG. 16 depicts thefirst member being substantially disposed within the second member,while FIG. 17 depicts the first member being only partially disposedwithin the second member.

In operation of this second embodiment, fluid is introduced into hollowinterior 304 in the direction indicated by arrow 314. Upon thesufficient build up of pressure created by the flow of the fluid, theclosed end 312 design of second member 308 forces the fluid to move inthe direction indicated by arrow 315 (best shown in FIG. 17) and throughthe flow channel defined by the threaded configuration of the twomembers 320, 308. The degree of overlap of the two threaded geometriesdetermines the hydraulic resistance, and thus the flow rate of thefluid. Therefore, the high overlap shown in FIG. 16 would result in alesser flow rate than that of the low overlap depicted in FIG. 17.Nevertheless, the fluid ultimately emerges from the resistor design asillustrated by arrows 316. It is envisioned that in other examples inaccordance with this embodiment of the present invention the shapes ofthe two members may vary, as can the particular thread design employed.

In a third embodiment the adjustment of flow rate is realized byadjusting the cross-sectional geometry of the resistor. However, unlikethe above discussed first embodiment where the cross-sectional geometryis adjusted by lengthening filament 52 in order to decrease itsdiameter, this third embodiment varies the cross-sectional geometry of atube 402 by changing its internal pressure. Once again, the thirdembodiment will be discussed with respect to pump 20; however, it may beutilized in combination with any implantable pump. As shown in FIGS.18-20, in accordance with this third embodiment, resistor 32 includes anelastic tubular element 402 disposed in a capillary 404. As best shownin FIG. 20, the tubular element 402 extends through capillary 404 and isfixed at its ends by sealing elements 406 and 408. As shown in FIGS. 18and 20, the tubular element 402 is situated so as to define aring-shaped flow channel 410 through capillary 404. However, like theabove discussed first embodiment, the tube may be positionedeccentrically, thereby forming a sickle-shaped flow channel 410, asshown in FIG. 19.

In operation, fluid flows in the direction indicated by arrows F, and issubjected to the flow channel from entrance 412 to exit 414. Once again,the effective length of the resistor extends along the portion wheretube 402 and capillary 404 overlap. The diameter of tubular element 402depends upon its internal pressure P1. Thus, the flow rate of the fluidcan be affected by pressure being applied or reduced to the inside oftube 402. Rising the pressure will increase the outer diameter of thetubing and thus will have the effect of reducing the flow rate.Similarly, lowering the pressure will decrease the outer diameter of thetubing and increase the flow rate. It is noted that tubular element 402will have a particular resting diameter (i.e.—with no pressure beingapplied). The design of this third embodiment will be subject to theflow rate calculations discussed above in relation to the firstembodiment. Specifically, in the design shown in FIG. 19, adjusting thetubing between approximately eighty five percent (85%) to ninety percent(90%) of the overall inner diameter of capillary 404 will result in anapproximate flow rate variation of 1 to 25, which is the desired ratiofor an implantable pump. However, it is to be understood that theoperation of this third embodiment will be substantially opposite tothat of the first embodiment. Clearly, rather than decreasing thediameter of tube 402 from its resting diameter, this third embodimentaims to increase the diameter. Thus, operation of tube 402 will move thesystem from a state in which the flow rate is greater to a state wherethe flow rate is lesser. This is contrary to the first embodiment.

Any means suitable for rising and lowering the pressure to the inside oftubular element 402 can be utilized. For example, it is envisioned thata piston or bellows assembly may be utilized, or that a chemicalreaction may be employed to achieve the pressure differential.

In a fourth embodiment the adjustment of flow rate is realized byproviding an insert 502 having a longitudinally varying cross section.By moving the insert 504 along the longitudinal axis of a capillary 504,the hydraulic resistance of resistor 32 is changed. Once again, thefourth embodiment will be discussed with respect to pump 20; however, itmay be utilized in combination with any implantable pump. As shown inFIGS. 21-24, in accordance with this fourth embodiment, resistor 32includes the aforementioned insert 502 positioned within a capillary504. In one example of this fourth embodiment, as is shown in FIGS. 21and 23, insert 502 is depicted as having a conical shape, and iscentrally located within capillary 504. Thus, the cross section ofinsert 502 varies across its longitudinal axis and the design forms aring-shaped flow channel 506. This insert is fixed at its ends to twomovable piston-like attachments 508, 510. However, another example isshown in FIGS. 23 and 24, in which insert 502 may be positionedeccentrically resulting in a sickle-shaped flow channel 506. In thisexample, insert 502 is fixed at its ends to two movable fixations 512,514.

In operation of both examples, fluid flows in the direction indicated byarrows F, and is subjected to the flow channel from entrance 516 to exit518 (i.e.—the aforementioned effective length). While theabove-discussed equations relating to the flow rate do not necessarilyapply to this embodiment, it is clear that the width of flow channel 506may be varied by moving insert 502 in the direction of the axis ofcapillary 504. For example, as shown in FIG. 23, movement of insert 502in the direction depicted by arrow A will cause a decrease in the widthof flow channel 506, and thus a decrease in the flow rate of the fluid.Alternatively, movement of insert 502 in the direction depicted by arrowB will cause an increase in the width of flow channel 506, and thus anincrease in the flow rate of the fluid.

It is noted that the movement of insert 502 may be achieved in differentfashions depending upon the type of design utilized. For example, asshown in FIG. 23, piston-like attachments 508, 510 are preferably movedby providing a suitable pressure thereto. However, as shown in FIG. 24,movable fixations 512, 514 may also be utilized that are moved byproviding a mechanical force thereto, from source such as a hydraulic,electrical or mechanical source or the like. Various means may beemployed for providing movement to insert 502, including those discussedherein and others that would be well known to those skilled in the art.For example, once again, magnetic forces may be employed for movinginsert 502. Finally, insert 502 may include a varying cross section thatcreates a substantially smooth longitudinal surface, as shown in thefigures, or, insert 502 may be comprised of several non-congruent crosssectional portions. The latter configuration would provide an insertthat has several different stepped sections. Thus, moving a firstsection into capillary 504 having a relatively large cross section wouldmost likely reduce the flow rate, while moving a second section oflesser cross section would increase the flow rate.

In a fifth embodiment the adjustment of flow rate is realized byadjusting the cross-sectional geometry of an insert being constructed ofan electroactive polymer (EAP). For example, such an insert may beconstructed of polyanilin, polypyrrol, or the like. This type ofmaterial is also known in the art as an artificial muscle. Essentially,the diameter of this EAP insert may be changed by applying an electricvoltage thereto. In accordance with this fifth embodiment, the voltageapplied to such an EAP insert may be between approximately zero (0) andtwo (2) volts, but may be as much as seven (7) volts. Once again, thefifth embodiment will be discussed with respect to pump 20; however, itmay be utilized in combination with any implantable pump. As shown inFIGS. 25-28, in accordance with this fifth embodiment, resistor 32includes an insert 602, which is constructed of EAP, positioned withincapillary 604. FIGS. 25 and 27 show a first example where insert 602 iscentrally located in capillary 604, while FIGS. 26 and 28 show a secondexample where insert 602 is eccentrically located in capillary 604.Further, the first example includes an insert 602 with one end fixed ata stationary attachment 608 and the other end fixed at movableattachment 610, while the second example includes an insert 602 withboth ends fixed to movable fixations 612, 614.

In operation of both examples, fluid flows in the direction indicated byarrows F, and is subjected to the flow channel from entrance 616 to exit618 (i.e.—the effective length). The width of flow channel 606 may bevaried by varying the voltage between the ends of insert 602. Suchapplication of voltage causes insert 602 to lengthen, which therebyreduces its diameter. Essentially, in accordance with this fifthembodiment, insert 602 would act as an electrode, while capillary 604may act as a counterelectrode. As has been discussed several timesabove, the decrease in the diameter of an insert similar to insert 602necessarily decreases the hydraulic resistance in capillary 604 andincreases the fluid flow rate. It is noted that the calculationsrelating to the first embodiment above may be useful in determining theproper sized insert 602 for use in examples of this fifth embodimentthat utilize an insert 602 and capillary 604 that each have circularcross sections.

The various embodiments of resistor 32, in accordance with the presentinvention, should be positioned such that fluid housed in the slowrelease chamber of an implantable pump is forced to pass through it.This configuration allows for the implantable pump to operate in itsnormal fashion, with resistor 32 controlling the fluid flow rate.However, preferred constructions would situate resistor 32 such that aninjection into a bolus port or the like would not be forced to passthrough the resistor. It is typically not required to control the flowrate of a bolus injection. Rather, such an injection is often intendedto be a quick and direct application of a medication fluid. For example,as shown in FIG. 7, resistor 32 is situated so as to capture fluidflowing from chamber 24, but not fluid directly injected into bolus port46. However, other constructions are envisioned. Furthermore, where theimplantable pump is utilized to withdraw spinal fluid, it is alsocontemplated to not force such fluid through resistor 32. In the pump ofFIG. 7, withdrawal of spinal fluid would occur through bolus port 46. Assuch, the fluid would not be required to pass through the resistor.

For each of the embodiments above, providing a controlling mechanism forselectively varying the flow rate of the medication fluid is envisioned.Many different such mechanisms are well known and widely utilized withimplantable devices for implantation into a patient's body. For example,prior art devices have shown that it is possible to utilize dedicatedhard wired controllers, infrared controllers, or the like, whichcontrollers could be used in accordance with the present invention tocontrol various elements, such as motor 282, to selectively vary theflow rate of the medication fluid. U.S. Pat. No. 6,589,205 (“the '205patent”), the disclosure of which is hereby incorporated by referenceherein, teaches the use of a wireless external control. As discussed inthe '205 patent, such a wireless control signal may be provided throughmodulation of an RF power signal that is inductively linked with thepump. The '205 cites and incorporates by reference U.S. Pat. No.5,876,425, the disclosure of which is also hereby incorporated byreference herein, to teach one such use of forward telemetry or theexchange of information and programming instructions that can be usedwith the present invention to control the pump and the variousaforementioned elements that are varied in order to affect the flowrate. However, it is noted that similar external controllers may also beutilized. Such controllers can send control signals wirelessly (such asby IR, RF or other frequencies) or can be wired to leads that are nearor on the surface of the patient's skin for sending control signals.Furthermore, a pump in accordance with the present invention may includesafeguards to prevent the inadvertent signaling or improper programmingof the pump. For example, the present invention could utilize a securepreamble code or encrypted signals that will be checked by software orhardware used for controlling the pump or even dedicated only forsecurity purposes. This preamble code would prevent the inadvertentvarying of the flow rate of the fluid from the pump, from being causedby outside unrelated remote control devices or signals and by othersimilar pump controllers. Other safety precautions may be used, such aspasswords, hardware or software keys, encryption, multiple confirmationrequests or sequences, etc. by the software or hardware used in theprogramming of the pump.

The electronics and control logic that can be used with the presentinvention for control of the motors and controllably displaceableelements used to vary the flow rate may include microprocessors,microcontrollers, integrated circuits, transducers, etc. that may belocated internally with or in the implantable pump and/or externallywith any external programmer device to transmit pump programminginformation to control the pump. For example, any external programmerdevice used to allowing programming of the pump. The electronics canalso be used to perform various tests, checks of status, and even storeinformation about the operation of the pump or other physiologicalinformation sensed by various transducers.

An external programmer device may also be avoided by incorporating thenecessary logic and electronics in or near or in the implantable pumpsuch that control can be accomplished, for example, via control buttonsor switches or the like that can be disposed on or below the surface ofthe skin. Of course, necessary precautions (such as confirmation buttonpressing routines) would need to be taken so that inadvertent changingof programming is again avoided.

A specific implantable pump 700, which incorporates the above discussedreduced size designs, as well as the above discussed infinitely variabledesigns of the present invention will now be described. Essentially,pump 700 is an implantable pump having certain novel characteristics.These characteristics allow for both the relative miniaturization andeasy construction of the pump. In addition, pump 700 incorporates one ofthe aforementioned resistor 32 designs into the specific embodiment.While pump 700 is indeed one preferred embodiment for use in accordancewith the present invention, it should be clearly understood that thepump could be modified to incorporate each of the resistor 32 designsdiscussed above in many different configurations.

As shown in FIGS. 29 and 30, pump 700 includes a housing constructed ofan upper portion 702 and a lower portion 704. The housing portions arepreferably constructed of a strong polymeric material, such aspolyetherehterketone, sold under the designation PEEK by Invibio of theUnited Kingdom. Other suitable biocompatible materials may also beemployed. Nevertheless, the particular material should be chosen so asto be capable of forming a two part housing that can be safely assembledwithout the use of a complicated double clinch assembly, a weldingprocess or the like. Clearly, safety is a very big concern in theconstruction of any apparatus inserted into the body especially onehousing an overdose of medication solution. Heretofore, implantable pumphousings have either been constructed of a metallic material, wherein awelding process is utilized for attaching the portions of the housingtogether, or a polymeric material, wherein a complicated clinchingassembly is utilized for attaching the portions of the housing together.For example, a metallic pump is typically constructed by weldingtogether two metallic halves of the pump housing. Similarly, as taughtin commonly owned U.S. Pat. Nos. 5,814,019 and 5,836,915, a doubleclinching assembly has been previously proposed for safely attaching thehousing halves of a polymeric pump.

In accordance with the present invention, it has been discovered thatutilizing a material such as PEEK may allow for a polymeric pump housingto be constructed without the use of any of the complicated attachmentprocedures. The elimination of such extraneous elements allows for pump700 to be smaller in size. For example, the elimination of theaforementioned double clinch safety feature allows for the overall widthof pump 700 to be reduced. Further, in certain embodiments, this mayalso decrease the overall weight of the pump, as well as the level ofcomplicity required in assembling same. As shown in FIG. 29, portions702 and 704 of the housing of pump 700 are constructed of PEEK anddesigned so as to be capable of simply screwing together. Moreparticularly, portion 702 includes an interiorly threaded extension 703for receiving an exteriorly threaded surface 705 of portion 704. Incertain embodiments, in addition to the threaded connection, a layer ofglue or other adhesive may be applied to the connection between portions702 and 704. Such an application may provide further assurance that thetwo portions do not inadvertently become detached. It is alsocontemplated that other less complicated attachment modes may beemployed. For example, in addition to the threadable connection betweenportions 702 and 704, a single clinch connection may be utilized. Inthis type of attachment, the two portions may include elements that aredesigned so as to snap fit together, and thereafter fixably secure theportions together.

As with the aforementioned generic pump 20 design, implantable pump 700further includes an interior having two chambers 724 and 726, eachchamber being separated by a flexible membrane 728. Chamber 724 isdesigned to receive and house an active substance such as a medicationfluid, while chamber 726 is designed to house a propellant that expandsisobarically under constant body temperature. Similar to above discussedgeneric pump 20, the expansion of the propellant in pump 700 displacesmembrane 728 such that the medication fluid housed in chamber 724 isdispensed into the body of the patient through the path defined by anoutlet opening 730 (FIG. 30), a cylindrical recess 764, a resistor 732(FIG. 31), a cylindrical recess 766 (FIG. 29), an outlet duct 734 andultimately an outlet catheter 736. Also in accordance with pump 20, pump700 further includes a replenishment port 738 covered by a first septum740, and an annular ring bolus port 746 covered by a second ring shapedseptum 748. The utility of each of these ports is substantiallyidentical to those of pump 20. For example, a passage 744 allows fluidinjected into replenishment port 738 to be introduced into chamber 724.In addition, like that of pump 20, it is envisioned that specificallydesigned injection needles and correspondingly situated septa may beemployed to increase safety, as discussed above.

Contrary to the aforementioned pump 20, pump 700 includes an undulatingmembrane 728 which cooperates with a similarly undulating interiorsurface 707 of portion 702. As best shown in FIGS. 29 and 30, interiorsurface 707 of portion 702 has an undulating surface that serves as thetop surface of chamber 724, while membrane 724 has a correspondingundulating surface that serves as the bottom surface of chamber 724.When chamber 724 is empty, membrane 724 fits flush against the similarlyshaped interior surface 707. This is best shown in FIG. 29. However,upon introduction of a fluid into chamber 724, membrane 728 is capableof flexing and allowing for the expansion of chamber 724. This is bestshown in FIG. 30. This undulating configuration of membrane 728 andinterior surface 707 of portion 702 allows for replenishment port 738and septum 740 to be situated at a lower position with respect to theheight of the pump. Essentially, a center portion of both interiorsurface 707 and membrane 728 are a convex shape allowing for portion 738and septum 740 to be set lower. At the same time, portions to the leftand right of this center portion are enlarged, taking substantiallyconcave shapes. This allows for the overall volume of chamber 724 toremain substantially similar in comparison to well-known implantablepumps. Operation of pump 700 also remains substantially similar to priorart implantable pumps being driven by a propellant. While the specificundulating design (i.e.—a convex or lower portion flanked by two concaveor higher portions), shown in FIGS. 29 and 30, is one suitableembodiment, other embodiments are envisioned. For example, other pumpsmay include surfaces and membranes that have corresponding shapes havingmultiple concave and/or convex portions.

The specific construction and cooperation of resistor 732 within pump700 is shown in detail in FIGS. 29-31. The resistor shown in thisspecific embodiment is akin to the above described first embodimentresistor. As best shown in FIG. 31, resistor 732 includes an elastic andresilient filament 752 situated in a capillary 754. Filament 752 extendsthrough capillary 754 and is attached on its ends to two spools 760 and762. Spool 760 resides within cylindrical recess 764 in fluidcommunication with opening 730 in portion 702, while spool 762 resideswithin a cylindrical recess 766 in portion 702. Recess 764 is in fluidcommunication with outlet opening 730 and hence chamber 724 (best shownin FIG. 30). Similarly, recess 766 is in fluid communication with outletduct 734, and hence outlet catheter 736 (best shown in FIG. 29). Thus,fluid will flow from chamber 724 through resistor 732, and out ofcatheter 736 to a target site within the body.

As best shown in FIG. 31, capillary 754 is preferably curved so as toforce filament 752 to one side thereof. Spools 760 and 762 are adaptedto wind filament 752 thereon and thus vary its cross section. As morespecifically discussed above, this varying in cross section varies theflow rate of fluid through capillary 754. In the embodiment shown inFIGS. 29-31, spool 760 is adapted to remain in a fixed position, whilespool 762 is adapted to be rotated. However, in other embodiments, bothspools may be adapted to be rotated. As best shown in the crosssectional view of FIG. 29, spool 762 is mechanically coupled to severalactuation components including being coupled via an axle 770 to a wheel772. A motor 774, like that of the above mentioned X15G, is employed toprovide rotation to wheel 772. A bearing 776 or the like may aid in therotation of axle 770, by guiding and providing smooth motion to axle770. In the embodiment shown in the figure, motor 774 receiveselectrical energy and control from an electronic unit 778, which, asdiscussed above, is controlled from either internally or externally ofthe body.

The aforementioned actuation components are held together and withinpump 700 through a specific cooperation that is best shown in FIG. 29.Essentially, ring septum 748 and an elastic element 780 are designed tohold the actuation components to pump 700. The actuation elements arepreferably housed so as to be a single module encompassing spool 762,axle 770, wheel 772, motor 774, bearing 776 and electronic unit 778.During assembly, this module is placed into a recess on pump 700 so thatone side abuts ring septum 748. With the module in place, septum 740 isattached to portion 702 by screwing a holder 782, which holds septum740, to portion 702 of pump 700, so as to form a threaded connection783. Holder 782 is preferably constructed of PEEK material like portions702 and 704. It is also contemplated that other modes of attachment maybe employed, such as, by adhesive or a combination of adhesive andthreads. Ring 780 of elastomeric material is preferably placed betweenholder 782 and electronic unit 778, and the cooperation thereof holdsthe aforementioned module between septum 748 and ring 780. Essentially,one side of the module is designed to cooperate with septum 748(i.e.—curved cooperation), while the other side is designed to cooperatewith ring 780 (i.e.—sloped cooperation). Thus, in the fully constructedstate, the module of actuation components is essentially frictionallyattached to pump 700.

The specific embodiment shown in FIGS. 29-31 also allows for an easyconversion from a variable flow rate pump to a fixed flow rate pump. Inuse, the manufacturer or user of the pump would simply remove theaforementioned module of actuation components. A spacer, insert or thelike may inserted into any cavity formed in the housing of pump 700,after the removal of the module. Filament 752 is also removed fromcapillary 754 and replaced with a small tube (not shown), constructed ofa material such as glass. The tube preferably has an outer diameterslightly smaller than the inside diameter of capillary 754, so as toallow a snug fit therein. Further, the tube may have any suitable innerdiameter, it being noted that the particular inner diameter sizedictates the flow rate of fluid through capillary 754. Thus, dependingupon the desired fixed flow rate, a particular tube having a suitableinner diameter should be selected. Finally, the tube should be capableof conforming to the preferable curved shape of capillary 754. Withthese simple modifications to pump 700, a relatively inexpensive fixedflow rate pump may be produced. This simple conversion allows for theuse of the majority of the components of pump 700 without requiring themodification of any. This is beneficial, because new molds or the likewould not be needed to change between pump designs.

A further preferred embodiment implantable pump is depicted in FIGS.32-34, and is designated with reference numeral 800. Pump 800 is similarin nature to the above-described implantable pumps, and is designed toemploy a resistor or restrictor module that operates to vary the flowrate of medicament from the pump. The restrictor modules for use withpump 800 will be discussed more fully below. Pump 800, in and of itself,operates in similar fashion to the previously described pump 700,although it does utilize some different structure and certain additionaland/or different components. Because of several differences and/oraddition of elements between pump 700 and pump 800, similar componentsand/or structure of pump 800 are not labeled with like referencenumerals to that of pump 700.

As is shown in FIGS. 32-34, pump 800 includes an upper portion 801forming an upper portion of a housing and a lower portion 802 which ispreferably designed to screw into portion 801, thereby capturing amembrane 803 therebetween, in a similar fashion to other embodimentsdiscussed above. However, in pump 800, a second membrane 803 a (bestshown in FIG. 41), is provided and preferably forms a pocket or balloonwith membrane 803. In other words, membrane 803 forms and upper barrierof the pocket, while membrane 803 a forms a lower barrier thatessentially conforms to lower portion 802. Upper portion 801 includes anupper surface 804 for receiving a restrictor module and a lower surface805 that defines an upper part of an upper or medicament chamber 806(best shown in the cross sectional views of FIGS. 33 and 34). Lowerportion 802 includes an upper surface 807 that defines a lower part of alower or propellant chamber 808 (or allows the pocket formed by membrane803 to remain adjacent thereto). In addition, pump 800 also includescertain of the other elements included in, for example, theabove-discussed pump 700, such as, a replenishment port 809 covered by afirst septum 810 and ring bolus port 811 covered by a second ring septum812. Upper surface 804 of upper portion 801 further includes twoapertures 813 a and 813 b for receiving screws 814 a and 814 brespectively, an upstanding circular ring extension 815 that forms ashoulder 816, an exit opening 817 from medicament chamber 806, and anentrance opening 818 for medicament to enter back into pump 800 andultimately dispensed to an outlet duct 819 for ultimate travel to thepatient in a manner to be discussed below.

It is noted that pump 800 utilizes a similar chamber and/or membranedesign as that of pump 700, and the other reduced size implantable pumpsdiscussed above, with a modified variable flow rate assembly that willbe discussed below. The chamber and/or membrane design of pump 800 maynot only be similar in design and functionality to that of the otherembodiment pumps discussed herein, but may also include any of thevariants of the chamber and/or membrane designs contemplated with regardto the other implantable pump designs discussed herein.

Pump 800 is preferably designed so as to operate in conjunction with oneor more restrictor modules to form an implantable infusion pump system.FIGS. 35-45 depict pump 800 in conjunction with a first restrictormodule 820. Restrictor module 820 is preferably removably coupled toupper portion 801 (with screws 814 a and 814 b) and includes severalelements utilized to vary the flow rate of an active substance dispensedfrom pump 800. More particularly, restrictor module 820 is a stand alonecomponent having several elements encased or encapsulated in a solidmaterial, such as a polymeric material like the above-discussed PEEKmaterial. In this regard, it is noted that each of upper portion 801,lower portion 802 and module 820 may be constructed of like materials,or certain of those components may be different materials. The module ispreferably designed with a central aperture which allows access ofseptum 810 and with an overall diameter that allows is to sit within theconfines of the area defined by septum 812. Module 820 preferablymonitors and varies the flow rate of a medicament or active substancedispelled from pump 800 in order to provide a patient with a particularprescribed flow rate of same. For example, module 820 may vary the flowrate of the medicament in response to a signal received from an outsidesource (e.g., handheld device), or in response to a condition placedupon the patient (e.g., change in pressure or temperature).

FIG. 35 shows pump 800 with a fully constructed restrictor module 820being mounted on surface 804 of upper portion 801, while FIGS. 36-38show different partial cutaways of pump 800 so that certain portions ofthe pump itself and module 820 are hidden or removed in order to depictthe various elements of pump 800 and those which are housed by module820.

As is best shown in the top cut away view of FIG. 38A, module 820includes a valve 821, a motor 822, and an offset cam or extension 823for imparting movement to valve 821. It is noted that motor 822 can beany suitable motor capable of inclusion within module 820. Thus, suchmotor must fit within the constraints formed by the overall small sizeand particular configuration of pump 800 and module 820. One suitablemotor 822 includes a gearbox ratio of 64:1 and is sold under the partnumber ADM 0620-2R-V6-05 by Dr. Fritz Faulhaber GmbH & CO KG ofSchoneich, Germany. Cam 823 is designed as an offset cam, such that onerotation of the cam by motor 822 may cause translation of valve 821.Many different configurations may be utilized, as those of ordinaryskill in the art would readily recognize. Whatever particular design foreach of the elements is utilized, each of these elements preferablycooperates so that operation of motor 822 causes movement of cam 823 inorder to actuate valve 821, which in turn causes variations in the flowrate of an active substance from pump 800 to a patient. The preferredcam shown is simply oblong in shape, such that a rotation of samesubjects valve 821 to contact with thinner to thicker sections of thecam, which causes the needed translation.

One example of a variation in the elements utilized in module 820 isshown in FIG. 38B. Specifically, that figure depicts an alternativeconstruction for cam 823, which includes an axle 823 a connected tomotor 822. Axle 823 a drives an eccentric cam body 823 b, which in turnrotates a bearing 823 c. As with most bearings, bearing 823 c includesan interior rotating portion, and an exterior portion which generallydoes not rotate. Certain portions of valve 821 are abutted against theexterior portion of bearing 823 c, and these portions are caused toactuate in a similar fashion as will be fully discussed below. In short,the rotation of axle 823 a by motor 822 causes the rotation of eccentriccam body 823 b and the interior portion of bearing 823 c. Because of theeccentric nature of cam body 823 b, bearing 823 c is caused to translateupon the rotation of the eccentric body. It is noted that thisparticular construction may allow for translation of valve 821 without arotating portion contacting any portion of the valve. Rather, theexterior portion of bearing 823 c simply translates and contacts valve821, without rotation.

As is shown in FIGS. 37-39B, valve 821 includes a double sided needleportion 824 disposed within a valve body 825 as the mechanism allowingfor the varying flow rate of an active substance being dispensed frompump 800. FIG. 37 shows portion 824 as consisting of two pieces 824 aand 824 b. In certain embodiments, one of the pieces (for example, piece824 b) may include a coating of a flexible material, such as rubber orsilicon. This coating may allow for cooperation within valve body 825(for example, during blockage of passages) without requiring veryprecise tolerances to be met. In other words, such flexible material mayconform to the interior of valve body 825. Although the multi-pieceformat is preferred for assembly purposes, a portion 824 consisting of asingle piece may also be employed. Valve body 825 consists of a hollowcore formed in the material encompassing the various components ofmodule 820. Needle portion 824 is preferably mounted within the hollowcore of valve body 825 by mounting members 826 a and 826 b. Moreparticularly, valve body 825 is molded into or milled out of thematerial (e.g., PEEK) forming the main body of module 820. Itscooperation with needle portion 824 creates a situation similar innature to that of well known needle valve assemblies, which have beenutilized in many different mechanical assemblies for some time. Forexample, as shown in the view of FIG. 39A, movement of portion 824 tothe left side of body 825 blocks all fluid flow through a passage 827 toa passage 828. These passages are routes that fluid flowing from pump800 must take, and will be discussed more fully below in relation to thepath of fluid from pump 800. Alternatively, as is depicted in FIG. 39B,movement of portion 824 to the right side of body 825 allows fluid flowfrom passage 827 to passage 828. Clearly, as those of ordinary skill inthe art would recognize, intermediate positions of portion 824 withrespect to body 825 may vary fluid flow accordingly. In this regard, itis to be understood that movement of portion 824 within valve body 825is generally transverse to that of fluid flow through valve body 825.

In addition, the nature of valve 821 smoothes out the flow of fluid to apatient upon actuation of double sided portion 824. This is bestillustrated in the view of FIG. 39A where movement of portion 824 to aclosed position simultaneously creates a space to the left of passages827 and 828, denoted by reference numeral 829. This space 829 receivesthe excess fluid which has gathered around passages 827 and 828 uponmovement of portion 853 to a closed position, rather than the fluidbeing pushed into the body of the patient when the valve is closing. Inthe case of a two piece 824 a and 824 b needle portion 824, duringassembly, one piece may be inserted into each side of the core formed inbody 825. Thereafter the pieces 824 a and 824 b may be assembledtogether through a snap connection or the like.

As is mentioned above, motor 822 and offset cam 823 are designed to moveportion 824 of valve 821 to the open position depicted in FIG. 39B uponactuation of the motor. The general offset nature of cam 823 essentiallypushes portion 824 upon its rotation in one direction, while rotation inthe other direction allows portion 824 to return to its original closedposition under the influence of members 826 a and 826 b. In this regard,members 826 a and 826 b connecting needle portion 824 to body 825 allowthe left and right movement depicted in FIGS. 39A and 39B without theloss of fluid from valve 821. These members may be constructed of apliable material, such as rubber or silicone, and are preferably biasedin a single direction. For example, mounting members 826 a and 826 b maybe designed so as to return portion 824 to the closed position shown inFIG. 39A. Alternatively, a secondary mechanism may also be provided tocause portion 853 to move back to the closed or open position. Suitablestructures may include leaf springs, additional motor mechanisms, or thelike. It is also noted that members 826 a and 826 b could be constructedof other materials, such as titanium, or could include both a metal anda polymeric material. Finally, members 826 a and 826 b could include acentral cavity including an oil (e.g., silicone oil) which may furtheraid in preventing the loss of fluid from valve 821.

Restrictor module 820 also preferably houses two pressure sensors 830and 831 (best shown in FIG. 35) that sit in sensor seats 832 and 833(best shown in FIGS. 40 and 41) respectively, a fixed flow resistor orrestrictor 834 (best shown in FIG. 40), an electronic board 835 havingvarious electrical components mounted thereon, and one or more batteries836. Pressure sensors 830 and 831 are preferably positioned and utilizedto measure the pressure of fluid flowing on either side of fixedrestrictor 834. For example, sensor 830 is shown positioned so as totake an initial pressure reading of a medicament or other activesubstance being dispelled from chamber 806, and sensor 831 is shownpositioned so as to take a pressure reading when the substance haspassed through fixed restrictor 834. This provides readings of thepressure of the fluid being dispelled from pump 800, and also of thepressure just prior to the fluid entering valve 821. Clearly, the moreclosed valve 821 is, the higher the pressure, and vice versa. Thesepressure readings are preferably processed by certain of the variouselectrical components disposed on board 835 in order to determine theflow rate of the active substance being provided by pump 800. Of course,there are many different fashions in which this may be done, and thoseof ordinary skill in the art would readily recognize that the methods ofcalculating the flow rate, as well as the electrical architectureemployed to do so, may vary accordingly. One preferred embodiment pump800 utilizes sensors 830 and 831 that are manufactured by IntersemaSensoric SA of Bevaix, Switzerland and sold under the part number MS5401. The battery or batteries 836 are preferably utilized to power thevarious elements of module 820 which require power. For example,batteries 836 may provide power to motor 822, any sensors 830 and 831being employed and the various electrical components, among otherelements. In the embodiment depicted in FIG. 35, batteries 836 arepreferably designed so as to fit within a cut out 837 formed in module820, and the two batteries are designed to power different elements.

In use, pump 800's operation (with module 820 attached thereto) is notunlike that of pump 700. An active substance or other fluid ispreferably dispelled from upper chamber 806 of pump 800 through exitopening 817 in upper portion 801. This opening is similar to that ofopening 730 of pump 700, and is preferably designed to cooperate with acorresponding entrance opening 817′ (best shown in FIG. 45) on theunderside of restrictor module 820. Likewise, an exit opening 818′ (alsobest shown in FIG. 45) on the underside of restrictor module 820 ispreferably designed to cooperate with entrance opening 818 in upperportion 801. This leads to fluid being sent through outlet duct 819 andultimately through a catheter (not shown) to a portion of the patient'sbody. In order to ensure proper alignment of these openings, apertures813 a′ and 813 b′ (best shown in FIGS. 44 and 45) formed in module 820are designed to align with apertures 813 a and 813 b in upper portion801 of pump 800, respectively. In addition, pump 800 includes openings852 and 854 (best shown in FIG. 32) located near protrusions 817 and818, respectively. These openings are designed to receive protrusions856 and 858 (best shown in FIG. 45). Thus, the design essentiallyincludes four elements which ensure alignment of module 820 on pump 800.Although many different attachment mechanisms may be utilized inconnecting module 820 to pump 800, screws 814 a and 814 b are shown inthe drawings. The major difference between the flow of a fluid dispelledby pump 800 and fluid dispelled by pump 700 is the route taken throughmodule 820, which will now be discussed.

FIGS. 38-43 depict the various passages for fluid flow through module820. Referring to FIG. 40, once fluid is allowed to pass into module820, it is preferably first fed through a first passage 838 to the firstpressure sensor 830 where an initial pressure reading is taken.Alternatively, a separate opening and passage may be provided for takingan initial pressure reading with first sensor 830, although this mayrequire a separate opening to be formed in portion 801 of pump 800.Subsequent to the initial pressure being taken, the fluid may passthrough a second passage 839 and into fixed restrictor 834. As is bestshown in FIGS. 40-41, fixed restrictor 834 includes a glass capillary840 or the like, in which is disposed a filament 841. Capillary 840 iscurved and filament 841 is pushed to one side thereof. As is discussedmore fully above, this construction lends itself well to reducing theflow of a fluid flowing therethrough. Instead of a capillary, a curvedpassage could be formed in the material of module 820 and filament 841could be disposed within same.

Once through fixed restrictor 834, the fluid preferably flows into apassage 842. This passage branches off to second sensor 831 (where asecond pressure reading is taken) and to passage 827 leading to theneedle valve 821. In addition, at least passage 839 includes a sectionwhich leads away from normal fluid flow. In this regard, it is to beunderstood that some fluid may flow in this direction, but upon thebuild up of fluid, the closed section will cause fluid to run in thecontemplated direction. These ancillary passages may be provided duringthe manufacture of module 820, as will be discussed more fully below.Once delivered to valve 821, the position of portion 824 within body 825determines the flow rate to the patient. It is noted that absent someoutside forces (e.g., valve 821 reducing the flow rate), the maximumflow rate of the fluid will always be its initial flow rate from chamber806 reduced by the fixed flow restrictor 834.

FIGS. 42 and 43 further illustrate the path taken by fluid exiting valve821. More particularly, fluid exiting valve 821 enters passage 828, andthen passes into a passage 843 which leads the fluid out of module 820.Thereafter, the fluid is allowed to pass into passage 844 of pump 800and through outlet duct 819. This ultimately leads to the fluid beingdelivered through a catheter (not shown) to a patient site. It is to beunderstood that any catheter may be employed, including, but not limitedto, one or two-piece catheters. In addition, a specific connectionmechanism between such catheter and outlet duct 819 of pump 800 may beemployed. For example, U.S. Pat. No. 5,423,776 to Haindl, the disclosureof which is hereby incorporated by reference herein, teaches a flexiblecoupling for coupling a flexible catheter to a port that may be utilizedin conjunction with the present invention.

Manufacture of pump 800 and restrictor module 820, may be accomplishedin many different fashions. For example, the various elements of module820 may positioned in the configuration depicted in the figures, andthereafter injection molded with a material such as the above-discussedPEEK material. Other suitable materials may also be utilized.Alternatively, a mold may be utilized to form a shell of material, inwhich the various elements are disposed. This shell of material is shownin FIG. 46. Subsequent to either of the above molding steps, thenecessary passages for allowing the normal flow of fluid through module820 may be drilled in the material. Because of the relatively smallnature of module 820, this drilling process preferably includes drillingfrom the exterior of and into the material forming module 820. This ispreferably done multiple times, from different angles, in order to formthe necessary connected passages forming the flow path. Once thenecessary passages are created and a suitable flow path is embedded inmodule 820, certain of the remaining and unnecessary exterior openingscreated by the drilling processes are closed up with epoxy or some othersuitable material. This method of manufacturing module 820 is evidencedin the aforementioned passage 839 which includes the passage extendingaway from the fluid flow path. Of course, certain openings remain, suchas the openings 817′ and 818′ which allow fluid to flow from chamber 806and into module 820 and fluid to flow from module 820, respectively. Inaddition, as is alluded to above, valve body 825 is preferably eithermolded or milled into the material of module 820. Thus, restrictormodule 820 is a single stand alone component capable of cooperation withpump 800.

FIGS. 44 and 45 depict exploded views of the cooperation of pump 800 andmodule 820. The affixation of module 820 to pump 800 is preferably doneso that the components cannot become dislodged at any point during use.As is shown, screws are utilized to fixably connect the two components,with the screws not only attaching module 820 to pump 800, but alsoclamping circuit board 835 to module 820 (as best seen in FIGS. 35 and36), and thereby holding sensor 830 in seat 832 and sensor 831 in seat833, as well as motor 822 in its seat 822 a in module 820 (see FIG. 46).Alternatively, such sensors may be affixed in their respective seatabsent force provided by the circuit board. Whatever the attachment ofmodule 820 to pump 800, such is preferably designed so that the neededcooperating passages of pump 800 and module 820 (i.e., 817/817′ and818/818′) not only line up, but create relatively tight interfaces thatdo not allow inadvertent fluid leakage. O-rings may be provided not onlyat these connections, but also in the connections between the sensorsand the seats.

As is shown in FIGS. 36, 37, and 42-45, pump 800 may include a cap 845which snaps into shoulder 816 of upper surface 804. This cap preferablyprovides a cover for module 820 from the environment of the human body.In addition, it is to be understood that certain or all elements ofmodule 820 (e.g., batteries 836, motor 822, sensors 830 and 831, circuitboard 835, etc.) may be packaged in a hermetically sealed package orpackages (schematically illustrated as element 844 b in FIGS. 49A and49B), which are conventionally employed in implantable medical devices.Those of ordinary skill in the art would recognize the many differenttypes of hermetically sealed packages that can be employed in thepresent invention. Nonetheless, as will be discussed more fully below,certain elements (e.g., an antenna 844 c) may need to breach the barriercreated by such packaging (but remain under cap 845) in order to allowpump 800 and module 820 to operate properly.

FIGS. 47 and 48 more specifically depicts one suitable circuit board 835for use with module 820 and pump 800. As mentioned above, this boardincludes several electronic components including a processor chip 846, amemory 847 for storing a program to be run by chip 846, a capacitor 848for storing energy from batteries 836, a first amplifier 849 forboosting the signal of sensor 830, a second amplifier 850 for boostingthe signal of sensor 831, a dual channel analog to digital converter 851for converting analog signals received from sensors 830 and 831 todigital signals, input pads 853 useful in loading a desired program tomemory 847, a power section 854, a motor driver section 855 and a radioreceiver/transmitter section 856. Sensors 830 and 831 include pads whichelectrically connect with traces provided on the underside of board 835.While FIGS. 47 and 48 depict an actual illustration of a workingembodiment board 835 (with conventional circuit traces, resistors,contact points, etc. . . . ) those of ordinary skill in the electricalarts would recognize the many different types of connections and circuitelements that may be employed to effectuate the desired functionality ofthe pump as shown in FIGS. 49A and 49B.

FIGS. 49A and 49B depict a block diagram illustrating the generaloperation of module 820 and pump 800. As is clearly shown in thosefigures, processor chip 846 is provided with the information garnered bysensors 830 and 831 so as to provide an instantaneous indication of flowrate through the fixed flow restrictor 834. The flow rate desired forthe patient is fed to the processor by line 844 a and compared in theprocessor to the rate detected across the fixed flow restrictor. If thedesired rate is different from the current rate flowing through thefixed flow restrictor (as detected by sensors 830 and 831), motor 822 isactuated to move portion 824 of valve 821 and thusly effectuate a changein the flow rate. Motor 822 varies portion 824 of valve 821 until thesensed flow rate across the fixed restrictor equals the desired rate, atwhich point motor 822 stops until there is a new flow rate desired, atwhich time the above process repeats. Although many different types ofprocessor chips may be utilized in module 820, such must conform to thesize and shape restraints of pump 800. For example, chip 846 depicted inthe pictures is designed to fit onto the upper portion board 835 betweenthe board and cap 845. The particular chip shown is manufactured byMicrochip Technologies of Chandler, Ariz. and sold under part no.PIC18LF2580.

The above-noted operation of module 820 may be designed so as to be anintermittent process, rather than a continuous process. For example, inone embodiment, module 820 is designed to take pressure readings withsensors 830 and 831 once every fifteen (15) minutes. Likewise, in thesame embodiment, module 820 is designed to actuate valve 821 once perhour. This type of operation would facilitate an average desired flowrate of medication, rather than a real time monitoring and correcting ofsame. Operation in such a fashion may dramatically improve battery lifeand the overall working life of the various components of module 820.However, it is to be understood that module 820 may be configured so asto operate at any time interval, including in real time. As is shown inFIGS. 49A and 49B, module 820 preferably also allows for the monitoringof system temperature, battery voltage, and power supply voltage. Thesensors utilized in monitoring these conditions are labeled withreference numerals 844 d, 844 e, and 844 f for clarity purposes in FIGS.49A and 49B. Any suitable sensors may be employed for these purposes,and readings may be taken at any time interval. For example, oneembodiment takes such readings every one (1) second to ensure the healthof the system. In addition, it is contemplated to turn theradio/receiver components on and off every so often (e.g., every 15secs.).

It is also to be understood that often times sensors 830 and 831 willinclude an offset in the electrical signals dispelled by each sensor.For example, in the above-noted preferred embodiment sensors, the offsetcan be as high as plus or minus 40 milivolts. Thus, in order to garneran accurate pressure reading, and thusly, an accurate flow rate reading,this offset must be periodically determined and corrected. One methodfor doing so includes closing valve 821 so that no fluid flow from pump800 to the patient occurs. This results in a build up of pressure inmodule 820, which, when equalized, results in identical pressures atsensors 830 and 831 respectively, and should result in identicalreadings from each sensor. However, because of the aforementionedoffset, the readings will often be different. Thus, the respectivereadings of sensors 830 and 831 are taken at this point, and fed toprocessor chip 846. The difference in the readings (if any) isregistered and then accounted for in further flow rate calculations. Assuch, the offset is periodically reset in order to ensure accuratemeasurements of the pressures and flow rates. This offset correctionprocess may be undertaken at any period or at any given interval. Forexample, in one embodiment, such offset correction process is undertakenonce a day.

One major benefit provided by pump 800 and module 820 is the fact thattotal drug delivery may be monitored by a doctor or patient. This iscontrary to well-known implantable pumps which require a painful andinvasive procedure to be performed in order to detect the amount ofmedicament dispensed to a patient. As is discussed above, the particularflow rate being dispensed to the patient is at least periodicallymonitored by module 820. In some cases, this flow rate is kept at anaverage flow rate for a particular time period. A controller (like thosediscussed below) may be designed to keep a running tab of the amount ofmedicament dispensed, based on the flow rate readings or average flowrate. Thus, the patient or doctor may be provided with a gauge (possiblybuilt into the controller) which gives a real time or periodicmeasurement of medicament dispensed or medicament remaining within pump800. The latter would most likely be based upon the initial amountprovided in pump 800. This is a very important benefit provided by pump800 and its cooperation with module 820.

The amount of medicament dispensed is therefore determined bymultiplying the average flow rate (or real time flow rate) by the timeat which the flow rate from pump 800 was such. All of the different timeperiods are accounted for and the overall amount is determined by addingeach of these individual amounts together. As is discussed above,readings by sensors 830 and 831 may be taken at any interval, forexample, every fifteen minutes. In order to maintain an average flowrate, these readings are taken and a correction of valve 821 position isonly done when the flow rate deviates from the desired flow rate by acertain amount. For instance, is certain embodiments, a correction ofthe flow rate is made when the flow rate deviates by 10% of the overallflow rate. Thus, if the pump is operating at 10% less of a flow ratethan that which is desired, a correction is made so as to level out theaverage flow. In that case, valve 821 would be actuated so as to allowfor a flow which is slightly higher than the desired flow. Thispreferably equalizes the average flow over the particular time. Ofcourse, if the average flow is 10% or more higher than the desired flow,valve 821 would be actuated to allow for a lower flow rate. Minordeviations in flow rate caused by wear of the components and the likecan also be dealt with through this method of monitoring and varying theflow. Once again, operation in this fashion prevents the constant use ofthe particular power source of pump 800, thereby extending its usefullife.

As noted previously, restrictor module 820 may be remotely controlled toproperly dispense a predetermined amount of an active substance to apatient. Such external controllers, for example, which transmit RF,magnetic or electric field, or other signals, are well known in the artand may be designed so as to be easily operable by a doctor, othermedical professional, or even the patient having pump 800 implanted intheir respective body. For example, FIG. 49A depicts pump 800 beingutilized in conjunction with a PC, while FIG. 49B depicts pump 800 beingutilized in conjunction with a handheld device. It is noted that thehandheld device may be any suitable device, such as a stand-alone deviceor one which incorporates other useful features. For instance, acontroller for use in connection with the present invention may beincorporated into a blackberry, PDA or other handheld device. An antenna844 c may be disposed between board 835 and cap 845, and associated withradio receiver/transmitter section 856 of board 835. Preferably, thisantenna extends through any hermetically sealed package that may beemployed, so that clear transmission is ensured. Operation of pump 800,and in particular restrictor module 820, may involve the implementationof different algorithms or programs in order to produce the desired flowrate from pump 800. Such are also well known in the art, and may also beprogrammed externally or hardwired into module 820. The aforementionedinput pads 853 may be useful in loading different programs into memory847.

It is noted that other designs for restrictor module 820 may beemployed, as can many different manufacturing processes. For example, itis envisioned to include more or less elements within module 820. Inaddition, it is noted that the depiction of module 820 shown in FIGS.35-46 is merely but one embodiment of a suitable module, and others areenvisioned which employ different shapes and/or sizes, as well asdifferent configurations of the elements disposed therein. It is also tobe understood that, while described above, as being constructed of PEEKmaterial or the like, pump 800 and/or module 820 may be of anybiocompatible material or combination thereof. For instance, upperportion 801 and the other portions of the main housing of pump 800 maybe a PEEK material, while restrictor module 820 is constructed of or thevarious components of module 820 are encapsulated with a metallicmaterial. Likewise, the attachment of module 820 to pump 800 may beaccomplished in many different fashions.

Finally, it is envisioned to provide a constant flow restrictor modulecapable of cooperating with a pump like pump 800. As is shown in FIG.50, module 820′ is capable of cooperating with pump 800. Essentially,this constant flow module 820′ employs a similar attachmentconfiguration for attaching to pump 800, as that of module 820 (e.g.,apertures 813 a′ and 813 b′ which cooperate with screws 814 a and 814 bdiscussed above), but does not include the various elements useful invarying the flow rate of fluid dispelled from the pump. Rather, as isshown in FIG. 50, module 820′ employs a similar overall size and shape,but only includes a single fixed flow restrictor 834′, which includes afirst side 834 a′ for receiving a fluid from chamber 806 and a secondside 834 b′ for dispelling fluid for ultimate delivery through outletduct 819 of pump 800. Thus, in use, fluid dispelled from chamber 806 ofpump 800 is fed through restrictor 834′. It is specifically contemplatedto provide a module 820′ which only allows for a specific flow rate, andsuch flow rate may be deliberately designed to be less than that capableof being produce from chamber 806 of pump 800. Essentially, the flowrate of fluid through module 820′ is dictated by the diameter ofrestrictor 834′, with larger diameters allowing faster flow rates andsmaller diameters allowing for slower flow rates. It is to be understoodthat, like fixed flow restrictor 834, restrictor 834′ may employ afilament to further reduce the flow rate of fluid passing therethrough.FIG. 51 depicts pump 800 with module 820′ attached thereto, and it is tobe understood that cap 845 may further be connected to pump 800 in afully constructed and ready to implant pump system.

A further preferred embodiment implantable pump is depicted in its fullyconstructed state in FIGS. 52-58, and is designated with referencenumeral 2000. Pump 2000 differs from pump 800 in its specificprogrammable module design. In particular, pump 2000 includes aprogrammable module that includes a hermetically sealed portion in orderto prevent inadvertent contamination of certain of the components of thepump when such is implanted in the body. All of this will be discussedmore fully below, as will the operation of pump 2000.

Turning now to the specifics of the further embodiment design, pump 2000includes an upper portion 2002 (best shown in FIGS. 82, 83, and 85), alower portion 2004, and a cover 2006 which is removably engaged with theupper portion. The cooperation of these elements, as well as othercomponents of pump 2000, will be addressed more fully below. Like otherof the pumps discussed above, pump 2000 includes a central septum 2008for use in refilling a medicament chamber, and a ring septum 2010 foruse in administering a bolus dose to a patient. While shown asring-shaped, septum 2010 may be many other designs, including one ormore circular holes, like septum 2008. Moreover, pump 2000 includes acatheter connector 2012 for use in fluidly connecting a catheter tolower portion 2004, which is also formed with a series of suture holes2014 for use in affixing pump 2000 to the human body.

Like in other of the embodiment pumps discussed above, upper portion2002, lower portion 2004, and cover 2006 may largely be constructed ofPEEK, metal, or the like. Septa 2008 and 2010 may be formed of siliconor any other material suitable for allowing for the necessary sealing ofthe ports the septa overlie, both prior and subsequent to theintroduction of a syringe, needle, or cannula therethrough. Likewise,connector 2012 may be many different materials, with PEEK or metal beingpreferable. Connector 2012 may also be of many different configurationsdepending upon the catheter that is ultimately connected to pump 2000.In addition, it is contemplated to form connector 2012 integral withpump 2000 or as a removable component.

FIG. 59 depicts pump 2000 with cover 2006 removed therefrom. As can beseen in this figure, as well as several others that follow, pump 2000includes a programmable module consisting of a hermetic enclosure 2016,a valve unit 2018, and an antenna assembly 2020. The programmable moduleis shown without the remainder of the elements of pump 2000 in FIGS.60-62. FIGS. 63-72 focus on hermetic housing 2016 and its components,and FIGS. 73-81 focus on valve unit 2018 and its components. Thesefigures and the elements shown therein will now be discussed in detail.

With reference to FIGS. 60-62, the components of programmable module2015 are arranged such that hermetic housing 2016 receives valve unit2018 within an appropriately sized recess 2022, and valve unit 2018receives antenna assembly 2020 on a top portion thereof (discussed morefully below). Hermetic housing 2016 is provided with a central aperture2024 that allows for access to the aforementioned central septum 2008.Moreover, programmable module 2015 is preferably sized such that it doesnot cover ring septum 2010 when assembled with the remainder of pump2000. In the particular embodiment shown, programmable module 2015 iscircular-shaped to cooperate with circular-shaped upper and lowerportions 2002 and 2004. However, it is to be understood thatprogrammable module 2015 may be of any shape necessary to cooperate withthe remainder of the components of pump 2000. For instance, it isenvisioned to provide a square-shaped or rectangular-shaped programmablemodule 2015 that would cooperate with like-shaped upper and lowerportions 2002 and 2004. Similarly, while aperture 2024 is shown ascircular for cooperating with circular central septum 2008, such canalso be of any different shape as dictated by the shape of the centralseptum.

Although hermetic housing 2016 and valve unit 2018 are two separatecomponents, they are fixed in place with respect to one another byvirtue of their cooperation with upper portion 2002. This cooperation isshown in FIGS. 60-62 despite the housing and valve unit being shownwithout the remaining components of pump 2000. Hermetic housing 2016 isshown as being constructed of an upper housing portion 2026 (best shownin FIGS. 60 and 61), a lower housing portion 2028 (best shown in FIG.62), and a bracket 2030, which are also shown individually in FIGS.66-70. These components are, in the preferred embodiment depicted in thedrawings, constructed of titanium, although any similar material may beutilized. For instance, it is envisioned that other embodiments mayemploy a hermetic enclosure formed of stainless steel or the like. Onthe other hand, valve unit 2018 is largely constructed of PEEK, which isutilized in certain of the other embodiments described above. Theformation of housing 2016 out of titanium or the like is dictated by theneed to protect the components housed within its interior.

With focus on FIG. 62, it is shown that hermetic housing 2016 includestwo connecting pins 2032A and 2032B extending from lower housing portion2028 for connection with upper portion 2002 of pump 2000. Valve unit2018 likewise includes pins 2034A and 2034B for connection with upperportion 2002, as well as an aperture 2036 for use in receiving afastener, such as a screw 2038. Screw 2032 is also designed for engagingupper portion 2002 of pump 2000. As is also shown in FIG. 62, a firstpressure sensor 2040 extends through lower housing portion 2028. Nowreferring to FIGS. 63-65, a second pressure sensor 2042 and a feedthrough 2046 extend through bracket 2030, and the bracket is formed withan aperture over which a flexible membrane 2044 is placed. All of theseelements and their cooperation with the remainder of pump 2000 will bediscussed more fully below.

As is noted above, FIGS. 66-70 individually depict upper housing portion2026, lower housing portion 2028, and bracket 2030, which cooperate withone another in order to form hermetic housing 2016. In particular, upperportion 2026 is shown in FIGS. 66 and 67 as formed with aperture 2024therethrough in order to allow for access of the central septum, andincludes a flat upper member 2048 and a circumferential lip 2050extending therefrom. As is best shown in FIG. 67, this at leastpartially defines an interior space within hermetic housing 2016 forreceipt of other components of pump 2000. As is shown in FIGS. 68 and69, lower housing portion 2028 includes a substantially flat lowermember 2052 and a central substantially cylindrical section 2054 whichcooperates with aperture 2024 to provide access to the central septum,while also sealing off the interior space of hermetic housing 2016.Lower housing portion 2028 is also formed with apertures 2056A and 2056Bfor receiving pins 2032A and 2032B, respectively, and an aperture 2058for allowing a portion of first pressure sensor 2040 to extendtherethrough. Both upper and lower housing portions 2026 and 2028 arealso formed with a slot for receiving and cooperating with bracket 2030.As is shown in FIG. 70, bracket 2030 is generally U-shaped and includesaperture 2060 through which pressure sensor 2042 extends, aperture 2062over which membrane 2044 lies, and aperture 2064 through which feedthrough 2046 extends. As is noted above, each of upper housing portion2026, lower housing portion 2028, membrane 2044 and bracket 2030 areformed of titanium, and are preferably affixed to one another in amanner in which housing 2016 remains hermetically sealed. In thepreferred embodiment shown, the three components are welded togethersubsequent to adding the other components of programmable module 2015within the interior space of the housing. Of course, other manners ofaffixing may be employed in the construction of housing 2016, however,such other manners should result in a hermetic sealing of the module.

FIG. 71 depicts a fully assembled hermetic housing 2016 with upperhousing portion 2026 and bracket 2030 removed therefrom. As can be seenin that figure, as well as in FIG. 72, which shows the same view withadditional components removed therefrom, hermetic housing 2016 includesa component support 2066 that is generally constructed of PEEK or Delrinand configured so as to receive and arrange certain components withinthe housing. For instance, as is best shown in FIG. 72, componentsupport 2066 includes an aperture 2068 for receiving a motor 2070, anaperture 2072 for receiving second pressure sensor 2042, a slot 2074 forreceiving first pressure sensor 2040, and slots 2076A and 2076B forreceiving batteries 2078A and 2078B, respectively. Moreover, hermetichousing includes, as is shown in both FIGS. 71 and 72, a circuit board2080 for controlling the operation of the other elements of the hermetichousing in response to information received from first and secondpressure sensors 2040 and 2042 and/or antenna assembly 2020. Circuitboard 2080 extends at least partially under component support 2066, butit is contemplated to form the board in many different shapes and/orsizes. Likewise, as is shown in FIG. 71, batteries 2078A and 2078B areeach covered by foam elements 2079A and 2079B, respectively. Theseelements preferably serve the dual purpose of protecting and keeping thebatteries in place. Of course, other elements may be employed to servethe same purposes. Feed through 2046 is also shown in FIG. 71. It is tobe understood that such element allows for a signal (from antennaassembly 2020) to be fed into housing 2016.

In addition, it is shown in FIG. 71 (and even more clearly in FIGS. 71Aand 71B) that motor 2070 is fitted with an eccentric gear or cam 2082and a ball bearing 2084, which cooperate with a nut 2086, adjustment2088, and membrane 2044. As shown in FIG. 71A motor 2070 consists of astepper motor 2070 a and a gearbox 2070 b. The motor also includes aconnector 2071 for affixing motor 2070 in place. Nut 2086 and adjustment2088 are shown in FIG. 71B, with a motor adjustment plate 2089 alsobeing shown. Plate 2089 is preferably affixed to component support 2066.When fully assembled, rotation of nut 2086 preferably moves adjustment2088 so as to allow for motor 2070 to impart greater or lesser forceupon membrane 2044. This operation will be discussed more fully below.

Valve unit 2018 is further depicted in FIGS. 73-81. Valve unit 2018includes a body 2090 constructed generally of a polymer, such as PEEK orthe like. As is noted above, body 2090 includes aperture 2036 throughwhich screw 2038 extends to affix valve unit 2018 to upper portion 2002of pump 2000. Pins 2034A and 2034B also extend from a bottom portion ofhousing 2090. In addition, body 2090 includes a slotted section 2092 inwhich antenna assembly 2020 is placed, a central opening 2094 throughwhich a double-sided valve (discussed below) is placed, an entranceopening 2096 (best shown in FIG. 79) for receiving fluid from themedication chamber of the pump, a pressure sensor opening 2098 (bestshown in FIG. 76) from which fluid can flow to pressure sensor 2042, andan exit opening 2100 from which fluid can flow back to the pump andultimately out of the catheter. It is noted here that each of theopenings in the valve body may include an O-ring or the like in order toensure a seal between the corresponding portions of pump 2000 they aremeant to fluidly communicate with. Moreover, it is also noted that whilea specific shape and size of valve unit 2018 is depicted in thepreferred embodiment shown in the figures, it is contemplated that manydifferent sizes and shapes may be employed. In fact, the specific sizeand shape shown is such so as to allow valve unit 2018 to properlycooperate with hermetic housing 2016. If housing 2016 changes, valveunit 2018 can change accordingly.

FIGS. 80A-80C depict valve unit 2018 with housing 2090 shown intransparent. The cooperation of pins 2034A and 2034B can be seen in thisfigure, as can the placement of a double-sided valve stem 2102 withinaperture 2094. Also shown are a duct 2103 allowing fluid that entersentrance opening 2096 to flow into contact with pressure sensor opening2098 (and thusly pressure sensor 2042), a duct 2104 (best shown in FIGS.80B and 80C) allowing fluid to flow from pressure sensor 2042 to valvestem 2102, and a duct 2106 allowing fluid to flow from valve stem 2102to exit opening 2100. Thus, fluid flowing into valve unit 2018 (1) issubjected to a pressure reading by sensor 2042, (2) has its flow ratevaried by valve stem 2102, and (3) exits opening 2100. It is to beunderstood that the various openings (including those in which pins2034A and 2034B are placed) and ducts are all formed within housing2090. Such housing may be molded or formed in separate pieces. Moreover,it is possible to mill or otherwise form housing 2090 from a solidmaterial block.

FIGS. 81A and 81B focus on valve stem 2102, which is made up of two coneportions 2108 and 2110. The two cone portions are preferably designed sothat they snap together or otherwise affix to each other. While coneportion 2108 is generally a solid portion, cone portion 2110 isconstructed of two individual components, i.e., stem portion 2112 andsilicone cone portion 2114. Moreover, cone portion 2108 is fitted at oneend with a resilient silicone disc 2116 and cone portion 2110 islikewise fitted at its end with silicone disc 2118. While silicone coneportion 2114 is useful in providing a seal when required (i.e., when noflow is desired from pump 2000), silicone discs 2116 and 2118 aredesigned to bias valve stem 2102 in a certain direction within aperture2094. Thus, movement of valve stem 2102 must be provided by an outsidesource. The silicone discs also act so as to seal opening 2094 so thatno fluid can escape therefrom during operation of pump 2000. Cone body2108 is also provided with fasteners 2120 a and 2120 b, while cone body2110 is provided with fasteners 2122 a and 2122 b. Cone body 2110 isalso provided with an adjustment screw 2124 which allows for anothermeans to adjust the ultimate operation of valve stem 2102. It is notedthat aperture 2094 is preferably formed at its ends with shoulders sothat after insertion of cone bodies 2108 and 2110 on opposite sides ofthe valve unit, application of nut 2124 and screw 2126, valve stem 2102is secured within body 2090. Moreover, adjustment of screw 2124determines the overall amount of that valve stem 2102 can slide withinaperture 2094.

FIGS. 82-85 depict the remainder of pump 2000. Specifically, FIGS. 82and 83 depict pump 2000 with programmable module 2015 removed therefrom,while FIGS. 84 and 85 show upper portion 2002 and lower portion 2004,respectively, uncoupled from each other. As can be seen in FIGS. 82, 83,and 85, upper portion 2002 is provided with apertures 2130A-F throughwhich screws 2132A-F are placed to affix upper portion 2002 to lowerportion 2004. For illustrative purposes only, screws 2132A-F are shownaffixed to lower portion 2004 in FIG. 84, without upper portion 2002also attached thereto. Moreover, upper portion 2002 is shown as beingformed with apertures 2134A and 2134B for receiving pins 2032A and2032B, respectively, of hermetic housing 2016, apertures 2136A and 2136Bfor cooperating with pins 2034A and 2034B, respectively, of valve unit2018, and aperture 2138 for receiving screw 2038 to affix valve unit2018 to the upper portion. As is best shown in FIG. 85, upper portion2002 also includes aperture 2140 for allowing fluid to flow intoentrance opening 2096 of valve unit 2018, and aperture 2142 for allowingfluid to flow back into the upper portion from exit opening 2100 ofvalve unit 2018. In a fully constructed state (like in FIGS. 82 and 83),those two apertures are provided with stems 2144 and 2146, respectively,for ensuring the communication with the apertures of the valve unit.These stems may include O-rings or the like in order to ensure a properseal between the apertures and the openings. Upper portion 2002 alsoincludes an aperture 2148 which cooperates with and receives a portionof pressure sensor 2040. Aperture 2148 preferably includes an O-ring orthe like to ensure a sealed cooperation with pressure sensor 2040.

FIGS. 86 and 87 depict cross-sectional views of upper portion 2002 andlower portion 2004 constructed together, while FIGS. 88 and 89 depictthe same cross-sectional views of a fully assembled pump. Upper portion2002 and lower portion 2004 cooperate so as to capture a propellant bag2150 comprising an upper membrane 2152 a and a lower membrane 2152 b.This is also shown in more detail in FIG. 91 and discussed more fullybelow. As is known in the art and described more fully above, saidpropellant bag is preferably filled with an isobarically expandingpropellant in order to provide a constant flow from the construct shownin FIGS. 86-89. While lower membrane 2152 b and an upper surface 2154 oflower portion 2004 essentially touch one another, upper membrane 2152 aand a lower surface 2156 of upper portion 2002 form a medicament chambertherebetween. When propellant contained within the propellant envelopefully expands, upper membrane 2152 a rests against lower surface 2156.However, when the propellant is not fully extended, as is shown in FIGS.86-89, a space between those two elements exists. Medicament may bestored in this space, and dispelled from the pump during the expandingof the isobaric propellant. Surfaces 2154 and 2156 are shown employingeither generally concave or combination concave and convex shapes. Theseconfigurations may aid in the overall reduction in the size of the pump(as is discussed above), but otherwise, may be of any configurationknown in the art. Among other things, FIGS. 88 and 89 show a connection2158 between upper portion 2002 and cover 2006. While this is shown as asnap-fit connection, it is to be understood that any suitable connectionmay be employed, including screwable connections or the like.

FIG. 90 is an exploded view of the constant flow module. In addition tothe elements already discussed in connection with FIGS. 82-89, FIG. 90depicts a resistor capillary 2160, filter capillary 2162, needle stop2164, and o-rings 2166. The latter two elements are useful in preventingover insertion of a needle, preventing medication from leaking out ofthe reservoir and maintaining propellant bag 2150 in place,respectively. Capillaries 2160 and 2162, on the other hand, are usefulin providing a maximum flow rate from the constant flow module. Filtercapillary 2162 is preferably an elongate filter which allows fluid topass therethrough, but prevents unwanted particles to do the same.Resister capillary 2160 is preferably an elongate tube with a relativelysmall diameter, so that fluid passing therethrough can only do so at amaximum flow rate. Both capillaries may be situated in an arcuatefashion within pump 2000, which allows for more length of each to bedisposed within the relatively small pump.

FIG. 91 depicts propellant bag 2150 in a more detailed exploded manner.As is shown in that figure bag 2150 includes already discussed upper andlower membranes 2152 a and 2152 b, respectively. An additional membrane2168 is shown preventing membrane 2152 a from contacting the medicationfluid directly as well as a refill pouch 2170. The latter element isdiscussed in more detail in U.S. patent application Ser. No. 12/609,385(“the '385 application”), the disclosure of which is hereby incorporatedby reference herein. Among other elements, pouch 2170 includes a septum2172, which is useful in initially filling it with propellant. The pouchis preferably designed to allow propellant contained therein to permeateinto propellant bag 2150 in which it is placed during assembly of thepump. It is to be understood that both upper membranes 2152 a and 2168,as well as lower membrane 2152 b may be of any construction. In apreferred embodiment, upper membrane 2152 a and lower membrane 2152 bare tri-laminate foils, which additional upper membrane 2168 is a PETfoil.

The construction of pump 2000 will now be discussed. First, septum 2008is placed in its appropriate location and secured with needle stop 2164.Thereafter, resistor capillary 2160 and filter capillary 2162 are placedinto upper portion 2002 using known methods, including the use of one ormore glue spots. The propellant bag formed by membranes 2150 and 2152 isthen filled with a propellant through any well known means. Forinstance, through the use of pouch taught in the above-discussed '385application. O-rings 2165 and 2166 are placed in the appropriate groovesin upper portion 2002 and lower portion 2004. The propellant bag is thenplaced between upper portion 2002 and lower portion 2004, and screws2132A-F are placed through apertures 2130A-F of upper portion 2002 andcarefully tightened. Septum 2010 is then placed in its appropriatelocations, which essentially creates the constant flow pump portion ormodule of the device.

Working with a fully constructed hermetic housing 2016 and valve unit2018, such components are placed together. That construct is then placedon upper portion 2002 so that the various pins of the hermetic housingand the valve unit align with the corresponding apertures of upperportion 2002. It is noted here that in addition to screw 2038 affixingvalve unit 2018 to upper portion 2002, other means may be utilized toaffix hermetic housing 2016 or valve unit 2018 to the upper portion. Forinstance, pins 2032A and 2032B may be designed so as to cooperate withafter-placed struts or the like in order to prevent the removal ofhermetic housing 2016 from the remainder of the pump construct. Withhermetic housing 2016 and valve unit 2018 in place, antenna assembly2020 and cover 2006 can then be added to the pump, which is then in afully constructed state.

During operation of pump 2002, a propellant placed between membranes2150 and 2152 is preferably caused to expand isobarically under normalbody temperature. It is noted here that other types of propellants canbe utilized, including other expanding gas propellants or evenmechanical pumping mechanisms. Whatever the case, a constant flow offluid is preferably then expelled through both apertures 2140 and 2148of upper portion 2002 (best shown in FIGS. 82 and 85). The fluiddispelled from aperture 2148 is utilized by pressure sensor 2040 to takean initial pressure reading of the fluid being dispelled from theconstant flow portion of the pump. The fluid ultimately dispelled fromaperture 2140 is first passed through filter capillary 2162 and thenresistor capillary 2164. The former prevented unwanted particulates topass through the remainder of pump 2000, while the latter provides thefluid that does pass through the filter capillary with a maximum flowrate. Once dispelled from aperture 2140, the fluid is introduced intovalve unit 2018 through aperture 2096. This fluid then passes throughduct 2103 en route to pressure sensor opening 2098 and thusly pressuresensor 2042, where a second pressure reading is taken. The fluid thenpasses through duct 2104 and into contact with valve stem 2102.Depending upon the positioning of the valve, the flow rate may or maynot be reduced. After passing around valve stem 2102, and in particularsilicone portion 2114, the fluid then travels through duct 2106, out ofexit opening 2100, and back to the constant flow portion of the pumpthrough aperture 2142. The pressure readings taken by pressure sensors2040 and 2042 are utilized by other portions of hermetic housing 2016(most notably the circuit board) to determine the flow rate based uponthe comparison of the first pressure reading from the first pressuresensor 2040 and the second pressure reading from the second pressuresensor 2042. If a change in flow rate is desired, motor 2070 is thenutilized to rotate the eccentric gear which in turn pushes membrane 2044engaged with screw 2126 of valve stem 2102. This interface causesmovement of the valve within valve unit body 2090. Because of theconfiguration of membrane 2044, movement is thus applied to valve stem2102 while maintaining the seal of the hermetic sealing of housing 2016.Ultimately, because of certain ducts located in upper portion 2002 andlower portion 2004, the fluid is ultimately dispelled through a catheterconnected with catheter connector 2012 to a particular area (or areas)of the body. As such, the cooperation among upper portion 2002, lowerportion 2004, hermetic housing 2016, and valve unit 2018 provides for afully programmable pump capable of varying flow rates therefrom.

During a refilling procedure in accordance with either pump 800 or pump2000, the output value of the first sensor (sensor 830 in the case ofpump 800 and sensor 2040 in the case of pump 2000) can be monitored inorder to confirm whether a refill needle or the like is properlypositioned (in replenishment port 809 of pump 800 and through centralseptum 2008 of pump 2000) or not. Essentially, the doctor or othermedical professional conducting the refill procedure may simultaneouslymonitor the output values provided by the respective first sensor byallowing for an external device such as a laptop, handheld device, orthe like to communicate with the pump. If the refill needle or otherapparatus is properly positioned, the first sensor will read a pressureof the fluid injected into the medication chamber of the respectivepump. This pressure reading will continue to increase until the refillprocedure is complete, which will also be the highest pressure readingtaken by the first sensor. This additional functionality of pumps 800and 2000 is an additional safety feature afforded by the devices. Whereother pumps employ intricate monitoring devices or the like to ensureproper positioning of a needle during a refill procedure, the presentinvention does not require any additional components to achieve the samegoal.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

The invention claimed is:
 1. A programmable module for use with animplantable pump comprising: a hermetic housing having a completelysealed interior, the interior including a first pressure sensor, asecond pressure sensor, an actuation mechanism, a motor, an offset cam,and a flexible membrane; a valve unit including a double sided needlevalve in contact with the flexible membrane, wherein operation of themotor and offset cam causes the flexible membrane to flex and theflexible membrane causes translation of the double sided needle valve.2. The programmable module of claim 1, wherein the hermetic housingincludes an upper portion, a lower portion, and a bracket, wherein thevalve unit is disposed within a recess formed by the bracket.
 3. Theprogrammable module of claim 1, wherein portions of the first and secondpressure sensors extend out of the hermetic housing.
 4. The programmablemodule of claim 3, wherein the portion of the second pressure sensorsextending out of the hermetic housing is in fluid communication with thevalve unit.
 5. The programmable module of claim 1, wherein the valveunit further includes first, second, and third openings.
 6. Theprogrammable module of claim 5, wherein one of the openings is incommunication with the second pressure sensor.
 7. The programmablemodule of claim 1, wherein the interior further includes at least onebattery and a circuit board in communication with the battery and thefirst and second pressure sensors.
 8. The programmable module of claim1, wherein the hermetic housing includes a duct formed therethrough. 9.A kit including the programmable module of claim 1 coupled with aconstant flow pump.